When a vehicle’s starter cannot get a vehicle going  in the morning, the problem can usually be traced to the battery, alternator, voltage regulator, or the electrical wiring that connects these components. The battery’s job is to provide electrical power for the starter motor when the ignition switch is turned. The starter motor gear engages the engine flywheel to crank and start the engine. The battery expends a considerable amount of energy each time it powers the starter motor, while the charging system (composed of the alternator and voltage regulator) provides current that restores the battery to full charge after it has used its energy to run the starter motor. All these components should be checked in no-start situations.

HINT: In some no-start situations, the problem may rest with the alternator belt, which, if loose, can reduce the current output of the alternator and cause the battery to run down.



When piston rings become so worn that they allow oil to seep into the combustion chamber on the intake stroke, hot combustion gases will blow down the cylinder on the power stroke. As a result, oil will be burned off and carbon deposits may form on the cylinder, pistons, and rings. Even worse, if the rings are damaged to the extent that they cut into the sides of the piston grooves, the piston assembly can be completely destroyed. For this reason, it is always preferable to replace the rings with new ones during an engine overhaul rather than simply reinstalling worn rings. Unlike older rings, new rings have quick-seating surfaces that allow them to control oil immediately.

HINT: When new piston rings are installed, it is recommend that worn valve stems and valve guides be replaced.



The days have long passed when an automobile could be purchased on the basis of kicking the tires and listening to the door shut. Gone also is the era when driveway mechanics could tinker under the hood to extract maximum performance from their vehicles. Today’s vehicles possess advanced technical systems that require trained technicians for maintenance and repair, guided by computer-based diagnosis. Regular maintenance also helps to ensure sustained, event-free driving that is both pleasurable and dependable. As advances in motoring technology continue to evolve, it is the goal of this column to inform our readers of automobile safety features, system advances and driving tips that will help them purchase and maintain their vehicles.

HINT: The majority of engine wear occurs while the engine is cold, so drive slowly until your vehicle’s engine is fully warmed.



The suspension component commonly referred to as a “shock absorber” performs the function that its name suggests.  In fact, it is the springs that actually absorb the road shock that is transmitted through a tire, wheel, hub, and spring mount. On the other hand, it is the job of the more accurately named “damper” to control the spring’s oscillations so that the tires are able to stay in contact with the road surface under most conditions. The result is a more comfortable ride, precise handling, efficient braking, and smooth acceleration. When the damper wears out, the spring oscillates at will, taking the tire with it. Periodic replacement of the dampers (shock absorbers) alleviates a bouncy ride and poor handling.

HINT: The term “where the rubber meets the road” is used metaphorically to point out the moment of truth.



Some vehicle owners express their holiday spirit by decorating their front grills with wreathes, ribbons, and images of Santa Claus or Rudolph. As delightful as these decorations are, they pose a potential danger to the efficient operation of the radiator. If pine needles from wreathes, threads, and other debris are allowed to collect in the radiator fins, the engine’s ability to properly dissipate heat will be compromised. Even a picture, sign, or lettering placed in front of the grill can prevent incoming air from removing heat from the radiator, resulting in an engine that is forced to run hotter than normal. At worst, the engine could overheat and the radiator could fail. That is no way to spend the holidays.

HINT: As long as you are thinking about your radiator, take the time to check the radiator fins for insects, feathers, and road debris that might be clogging the free flow of air. Once detected, remove the debris delicately with a tooth brush, without bending the fins.



 In order for engine oil to lubricate properly, it must flow freely. While thinner 5-weight oil pumps well while cold, it thins out as it gets hotter. As a result, it is less able to provide a cushioning film. On the other hand, thicker 30-weight oil provides a good cushioning film that does not thin out when hot; however, it is difficult to pump when cold. With all this in mind, auto manufacturers specifically recommend oil that provides the advantages of both thin and thicker oils. Multi-viscosity oil, such as 5W-30, is thin enough to pump when it is cold, but it thickens as it heats up. In any case, it is important to follow manufacturer recommendations.

HINT: Using the wrong oil viscosity is the single most common cause of premature engine wear.



Fuel injection systems rely heavily on information gathered about the motor’s current operating conditions in order to calculate the correct fuel mixture to optimize both power and fuel economy. So, it is understandable that a vacuum leak can disrupt the engine computer’s ability to get the information it needs to run correctly. Instead, a vacuum leak may force it to run a “rich” mixture as a means of protecting it from running “lean,” which may lead to engine damage caused by pre-detonation. As a result of unmetered air entering the engine and upsetting the fuel/air ratio, drivers are most likely to notice fluctuations in the idle and little effect at high speed. This rather subtle symptom should not be ignored.

HINT: A vacuum leak can typically be traced to a loose vacuum fitting, a ruptured vacuum line, a broken connector, or a faulty intake manifold.



It seems that car owners are holding on to their vehicles longer than ever before. According to a recent study, the average age for vehicles in this country has risen to 11.4 years, which is an all-time high. One reason that Americans are driving their cars longer includes the fact that cars and trucks are more reliable. However, car manufacturers know that demand will surge in the near future as fuel economy numbers continue to rise. For instance, in 2002, the average fuel economy of cars in the United States was 29 miles per gallon. A decade later, according to the U.S. Department of Transportation, the average fuel economy of new cars was 35.6 miles per gallon.

HINT: Over the next four to five years, sales of new vehicles will continue to be high as owners of older automobiles finally decide that it’s time to buy a new model.



 When it comes to describing steering wheel hand position, driving instructors refer to the numerals on a clock to show where drivers should hold their hands on the wheel. Traditionally, holding hands at “10 and 2” has been the recommended position. However, the introduction of the air bag has led to a change in thinking. Now, the recommended positions to hold the hands are at 9 and 3, with the thumbs placed along the rim rather than hooked around it. The reason behind the change in hand position has to do with the notion that a deploying air bag could send the hands of “10-and-2” positioned hands into the driver’s head and possibly break his or her thumbs.

HINT: With the constant possibility of air-bag deployment, drivers should never rest their hands on the hub of the steering wheel.



Brake pedals that feels spongy or that get substantially higher after repeated pumping likely have air in their hydraulic systems. To remove the air, the system must be “bled” by a technician. In rarer cases, a spongy brake pedal may be caused by brake fluid “vapor lock,” which is a condition that occurs when there is localized boiling of the brake fluid. This can result from the considerable heat generated by continued forceful braking combined with moisture in the brake fluid. Moisture, which can lower the boiling point of brake fluid, eventually may make its way into the system because brake fluid is “hygroscopic” (it attracts and absorbs water). When it does, the brake fluid must be replaced.

HINT: If moisture is not removed from hydraulic systems, it will eventually lead to corrosion of braking components, particularly the calipers.



One of the easiest ways to spot early signs of trouble and maintain the safety of your vehicle is to check your tires on a regular basis. While uneven tire tread wear can signal problems with the suspension or steering, underinflated tires can lead to poor handling, low gas mileage, and impeded braking ability. While it only takes a few minutes each month to check tire inflation and tread wear, relatively few car owners take the time to do so. In fact, a recent survey from the Rubber Manufacturers Association reveals that only one in six U.S. drivers is knowledgeable about basic tire care. If you are among the other five, it would certainly pay to find out.

HINT: Only eight percent of young drivers know basic tips for properly checking tire pressure, such as checking inflation  when tires are cold.



The heater core is the radiator-like component that heats the cabin of a vehicle by circulating heated coolant from the engine through tubes and blowing air over them into the cabin. One of the mystifying problems associated with the heater core occurs when the inside surface of the windshield persistently mists over. This problem can be traced to coolant that leaks from the core into the vents and then condenses on the cooler surface of the windshield. Ironically, vehicle owners often instinctively turn up the heater blowers in an effort to clear the misting; however, this response only compounds the problem. Once a correct diagnosis is made, the solution rests with removing and either repairing or replacing the heater core.

HINT: Because heater core repair can be costly, some vehicle owners choose to first try a coolant repair additive.



Head gaskets often fail due to engine overheating, which causes the cylinder head to swell and crush the head gasket. Detonation (spark knock) can also lead to head gasket failure, as a sharp spike in combustion chamber pressure can, over time, overload and crack the gasket armor that surrounds the cylinder. At that point, coolant and/or combustion gases leak. One way to pinpoint a head gasket leak is to perform a cylinder leak-down test (which involves removing the spark plugs and filling the cylinder with compressed air), which provides the added benefit of identifying which cylinder is leaking. This test also looks more closely at the cylinder for cracks and problems that might affect the success of the repair.

HINT: Head gasket replacement should include new head bolts, which are designed for one-time use.



When the charge light illuminates on the dashboard of a late-model vehicle, the vehicle owner might automatically assume that it is time to replace the alternator. However, experienced auto technicians know that it is best to test and diagnose the pulley before making a hasty decision. Nearly all late-model vehicles are outfitted with an overrunning alternator pulley (OAP) or an overrunning alternator decoupler (OAD), which is a one-way clutch that turns in one direction and locks in the other. An OAD performs in a similar manner, using a special clutch and spring that absorbs vibration to smooth out operation of the drive belt system. Either type (OAD or OAP) should be checked before replacing the alternator.

HINT: Overrunning alternator pulleys (OAPs) or overrunning alternator decouplers (OADs) can be tested on the vehicle with the belt attached.



If you have been following the development of the active safety systems being introduced into today’s vehicles, you may have come to the unmistakable conclusion that we are headed toward a future of self-driving automobiles. As automobile manufacturers continue to supplement systems such as forward-collision warning, park assistance, adaptive cruise control, and blind-spot monitoring with even more advanced and comprehensive systems, it seems that the goal is to eliminate the human element. Of course, there is good reason to do so. The vast majority of crashes are attributable to human error. Once vehicles become autonomous, we’ll all be able to sit back and let our cars get us where we are going based on current traffic, weather, and road conditions.

HINT: Not only will vehicles of the future be able to discern conditions with laser technology, they will be able to “talk” with one another.



Most vehicles produced after 1980 are equipped with oxygen sensors that measure the oxygen content of the vehicle’s exhaust gases. This information aids the engine-control computer in regulating the mixture of air and fuel burned in the engine, providing an optimal balance of power, economy, and clean exhaust. Oxygen sensors are relatively easy and inexpensive to replace; however, some vehicle owners ignore the recommended replacement intervals in their owner’s manuals because there is not a noticeable difference in the way the vehicle drives when the sensor stops functioning normally. Unfortunately, this is a false economy. The engine may use too much fuel as a result, as well as pollute the air needlessly. This hurts both the wallet and the environment.

HINT: The amount of oxygen that the engine needs varies in accordance with factors such as altitude, air temperature, engine temperature, barometric pressure, and the load on the engine.



When gauging your vehicle’s need for maintenance, do not use mileage as the sole criterion. Long stretches of highway driving are easier on engines than numerous short trips around town. The fact is that a fully warmed-up car traveling at a steady speed, which is typical of long highway drives, is operating at peak efficiency with little wear to the engine. On the other hand, it is estimated that up to 95 percent of an engine’s mechanical wear is sustained during warm-up and the first few seconds of driving (due to inadequate lubrication). Consequently, drivers who take numerous daily short trips in stop-and-go traffic  are subjecting their cars to more wear than the highway drivers who are on lengthy trips.

HINT: According to a recent AAA survey, only 6% of motorists felt they did the majority of their driving under severe conditions. Further investigation of their driving behaviors, however, led to the conclusion that 62% actually had.



Water pumps, which circulate coolant throughout the engine, are designed to consume as little engine torque as possible while providing the greatest possible coolant circulation. Thus, they must straddle the fine line between circulating too little coolant at engine idle (which causes overheating) and too much coolant at maximum engine speed (which wastes fuel and contributes to water jacket erosion). When water pumps fail, leaking shaft seals are the most common culprit. These leaks usually leave obvious coolant stains around the vent area and can be difficult to diagnose because they can be intermittently temperature- and pressure-sensitive. If a visual inspection does not lead to a diagnosis, a cooling system pressure tester may be used.

HINT: The second most common cause of water pump failure is shaft-bearing damage caused by the normal oxidation of lubricant on the bearing surfaces.



In 1903, the inventor of the windshield wiper, Mary Andersen, got her inspiration as she watched motorists wipe snow from their windshields with their hands. Ms. Andersen’s design called for the driver to use a lever on the inside of the automobile to manually activate “a swinging arm that mechanically swept off the ice and snow.” Eventually, the windshield wiper became the mechanized device that we still use today. However, all that may soon change as one car manufacturer envisions replacing wipers’ metal arms and rubber blades with a force field that repels water. The forward-thinking design will use ultrasonic sound to shake rain and debris from the windshield while providing savings in weight  and reduced complexity and wind drag.

HINT: Windshield blades  are vulnerable to degradation from the sun’s rays as well as dirt and grime.



 Young drivers responsible for taking care of automobiles for the first time in their lives should understand that oil is the lifeblood of their vehicle’s engine; therefore, it is vitally important to check oil levels regularly and change the oil as recommended. Dirty oil and/or low oil levels increase wear on internal engine components, leading to the potential for premature engine failure. Another very important maintenance step involves changing the air filter according to the owner’s manual schedule. A dirty air filter reduces engine performance and can cause the engine to overheat. Brake pads should be inspected for wear, and an appointment scheduled for service at the first sign of brake squealing. Waiting compromises safety and adds to repair costs.

HINT: If a vehicle’s worn shock absorbers are not replaced, extra stress is placed on all the car’s suspension elements, causing them to wear faster.



When the “check engine” light flashes on your dashboard, it generally involves the vehicle’s electronic control system. This is composed of a series of sensors (throttle, oxygen, knock, etc.) that monitor the various engine parameters; a computer that monitors the signals from these sensors and calculates any necessary adjustments; and a variety of actuators that carry out the adjustments. Typically, if the computer detects an electrical problem in the system, a warning light will come on in the instrument cluster to alert the driver. Concurrently, the computer will store in its memory a numeric code that identifies the specific electrical circuit in which the problem lies. By checking this diagnostic code, the technician can quickly identify the problem.

HINT: As a general matter, if the “SERVICE ENGINE SOON” light is red, turn off the engine and seek immediate assistance. If it is orange or yellow, make an appointment to have your vehicle serviced.



When it feels like a vehicle’s steering is pulling to one side, owners of older cars may suspect that they need a wheel alignment. However, it is best not to come to any premature conclusions. Cars that have been driven for 75,000 miles or more are likely to have endured significant wear to steering components such as ball joints, tie rod ends, and control arm bushings, so it makes sense to verify that there is no excess wear or damage to any of these components. If an alignment is performed on an automobile having one or more of these issues, the car may steer well for a time, but then may start to pull to one side shortly afterward.

HINT: Looseness in the suspension or steering that goes uncorrected can lead to rapid tire wear, cutting tire life by as much as half.



Tires have three types of designs: “symmetric” (mirror-image tread pattern); “asymmetric” (different tread designs on the inner and outer tread areas); and “directional” (tread design intended to function in only one rolling direction, noted on the sidewall with an arrow). When rotating (changing tire positions on the vehicle) a directional tire, it can be moved from front to rear on the same side without de/remounting it, assuming all tires are the same size. An asymmetric tire can be driven in either direction of rolling rotation and can be switched with any other as long as the marked outboard sidewall faces outward. Symmetric tires can be rotated without concern for location as long as their size is the same.

HINT: When asymmetric tires are rotated, they do not have to be demounted and remounted (as do directional tires that are swapped from side to side).



If a vehicle will not start, is it correct to automatically assume that the fuel pump needs to be replaced? To begin with, low voltage or a poor ground can cause low pressure and flow. A check of the battery can confirm that there is sufficient voltage on hand to drive the fuel pump. On the other hand, there may be good voltage at the pump, but a corroded or broken ground connection is causing a broken circuit that is leading the fuel pump to work inefficiently or not at all. It may also be the case that the powertrain control module (PCM) may be faulty, in which case it would be sending incorrect information to the fuel pump.

HINT: Vehicles that are hard to start, lack power, or stall frequently should have their fuel pumps (and related components) checked.



If a vehicle’s engine starts up and bluish or grayish smoke lingers noticeably, the matter needs to be looked into. This type of smoke is caused by oil burning in the combustion chamber, usually due to worn valve seals, valve guides, or piston rings, which are common conditions on high-mileage engines. A plugged PCV valve may also be the culprit. While faulty valve components limit the scope of the repair to the cylinder head, worn piston rings require a complete engine overhaul. If a heavy smoking condition is left uncorrected, a close watch should be maintained on the engine oil level. The burning oil will also likely foul spark plugs to cause rough idling, hard starting, and poor engine performance. The correct repair for internal oil leaking unfortunately is to remove the top half of the engine and replace some seals and gaskets.

HINT: White smoke coming from the tailpipe is usually indicative of a blown head gasket.



Problems with A/C systems often stem from low refrigerant levels caused by leaks. This potential culprit can be detected with a refrigerant recharge and dye injection (to locate leaks). If pressures at full charge are either too low or too high, it may be indicative of an internal restriction (of expansion valves and receiver driers, due to water vapor in the system that freezes and blocks refrigerant flow). With a full charge at 70 degrees F. ambient temperature, pressures should be about 35-40 psi on the low side and 145-160 psi on the high side. For every 5 degrees F. that the ambient temperature is warmer, pressures should be 5 psi higher, and vice versa.

HINT: If an A/C system is not fully charged, the compressor will often shut down automatically.



Because safety is foremost in the minds of vehicle manufacturers and drivers, it comes as good news that motor vehicle crash deaths among U.S. children ages 12 years and younger has dropped considerably in recent years. According to the latest data available to Centers for Disease Control and Prevention researchers from the National Highway Traffic Safety Administration, 43% fewer children died in car crashes during a recent eight-year period. Greater adherence to proper use of age- and size-appropriate child restraints is the primary reason for the improved safety record. However, there is still progress to be made. During the latest year for which data is available, one in three children who died in car crashes was not wearing a seat belt.

HINT: Children should be buckled into place with car seats, booster seats, or seat belts in the back seat, every time, regardless of how short the trip.



The longer that car owners hold on to their vehicles, the more likely it is that they will find that the polycarbonate lenses covering their headlight assemblies will undergo yellowish discoloration. We have acid rain, exposure to ultraviolet light, and multiple chemicals and elements on roadways to thank for the loss of the protective sealant and oxidation of the once-clear plastic. As a result of the discoloration, drivers will find that as much as 80 percent of the light from their headlights fails to reach the road ahead. At this point, headlamp cover discoloration becomes a safety issue. However, before having the plastic housing replaced, ask about wet-sanding and polishing procedures that deal with the problem.

HINT: Once the discoloration on a headlamp cover is removed, the application of a sealant will help prevent further deterioration.



Because brake pads and rotors are at the heart of any vehicle’s ABS, stability, or traction control system, they must be in good condition for these safety systems to work effectively. When pads become worn and/or rotors become rusted or corroded, brakes become more prone to “lateral brake run-out.” This term refers to side-to-side wobbling that occurs while rotors are spinning at high speed. As the brake pads make contact with high spots on the rotors, drivers will notice that there is more travel in the brake pedals before the pads can purchase enough bite to ensure good braking and effective utilization of ABS/stability/traction control systems. Careful inspection of rotors and pads at regular intervals is critical for safety.

HINT: It often makes good sense to replace damaged or worn rotors rather than resurface them (which only reduces their thickness and, therefore, makes them more prone to warping under high braking heat).



If you are involved in a car crash that damages your vehicle, you should not necessarily assume that your auto policy will pay for new or original equipment replacement parts. Many insurers are now requiring body shops to use less expensive recycled or aftermarket parts, some of which do not perform as well as the originals. Used and knockoff structural parts and safety-related parts should not be used if they compromise the structural integrity or safety of the automobile. With this in mind, you are encouraged to read the “limit of liability” section of your automobile policy. If original equipment manufacturer (OEM) parts are not specified for use, you might want to state your preference for new and original parts.

HINT: Many insurers pay for factory-fresh parts on vehicles up to one year old; some go up to three years.



Four-wheel drive was once a feature that was found only on military and safari-type vehicles. Now, thanks to technological advancements, nearly every auto manufacturer features some version of all-wheel drive somewhere in its product lineup. Now, the same thing may soon happen with 4-wheel steering (4WS). While some manufacturers have offered this sophisticated piece of road-handling technology in the past, more may be about to do so. In short, 4WS turns the rear wheels in the opposite direction at parking-lot speeds. At highway speeds, the rear wheels steer in the same direction as the front wheels. As a result, parking is easier and lane changes are swifter. In the near future, this feature may be as ubiquitous as all-wheel drive.

HINT: Believe it or not, the first 4-wheel drive vehicles appeared in the early 1900s, as did the first all-electric vehicles.



It is not uncommon  these days  for vehicle owners to hold on to their automobiles past warranty expiration dates. At this point, owners of vehicles with 100,000 or more miles under their belts may not even have factory-recommended service intervals to refer to. If so, they should rely on the experience of trusted auto technicians for maintenance guidance. Older vehicles will likely benefit from changing the engine oil, transmission fluid, coolant, and brake fluid  before additives lose their ability to stave off corrosion and unwanted buildups. If they have not already been replaced, spark plugs and oxygen sensors may also be due for replacement. Belts/tensioners, shocks/struts, drivetrain seals, and other components also should be examined  to forestall costly repairs.

HINT: If overrunning alternator decoupler pulleys or one-way clutches found on some late-model vehicles fail, it can lead to premature wear of other accessory drive components, a no-charge condition, or a weak battery.



The Mass Air Flow (MAF) sensor measures the amount of air that enters a fuel-injected engine and transmits the information to the engine control module (ECM), the vehicle’s on-board computer. The MAF works by virtue of a thin, heated wire mounted in the air stream that experiences heat reduction as incoming air increases. As the electrical current supplied to the “hot” wire is changed by increased air flow, the ECM detects this air flow variation through current and voltage changes. While some might assume that a service light would provide the first indication of any problem with MAF, poor idle, loss of performance, and stalling may be the first indicators that the MAF may be failing.

HINT: The primary cause of MAF failure is a contaminated hot wire.



The payoff for older vehicles that have undergone regular engine oil (and filter) changes is reduced (or little) wear between the cylinder walls and piston rings. Otherwise, gases that seep into the combustion chamber can cause carbon deposits that build up on the crown of the pistons, valves, and head. If these carbon buildups are substantial, they can cause turbulence in the chamber, hot spots, and even increases in the compression ratio. Newer vehicles with combustion chambers of advanced design and higher compression ratios are likely to be more vulnerable to these problems. Fortunately, professional engine de-carbonization can help remove deposits from the air intake, fuel delivery/injectors, intake manifold, valves, piston rings, and combustion chambers.

HINT: If gases from the crankcase leak into the combustion chamber, it can lead to damage of the catalytic converter and O2 sensors.



Among the most important and overlooked components on any vehicle are the threaded fasteners that secure the wheels to the hubs. It probably doesn’t help their status that these wheel fasteners are most often referred to as “lug nuts.” Whatever name they go by, wheel fasteners must be properly sized and installed to ensure sufficient engagement of the threads and proper seating. Conventional wisdom dictates that the minimum engagement length of a wheel bolt should be equal to the diameter of the fastener’s threads; however, deeper thread engagement is preferred for added safety. In addition, the seating style (conical, radius, or flat-seat) should match the base of the fastener head to the wheel’s fastener pocket. Also, avoid over- or under-tightening.

HINT: If wheel fasteners are tightening while a vehicle is on the ground (not on a lift), even a slight lateral load in the wheels will throw off the precise centering of the wheel fastener seats.



Whenever a spark plug fires, the plasma of the spark erodes the electrodes, causing the gap to increase. In time, the enlarged gap requires more energy to fire the plug, which can exact a toll on the coils. For this and other reasons, spark plugs should be replaced as needed. While this may seem to be a simple procedure that any home mechanic may do on his or her own, spark plug replacement may not be as simple as it seems. To begin with, attempting to remove the spark plugs when the engine is hot can damage the plugs and the engine head due to different rates of thermal expansion. Having an experienced technician perform the work eliminates unnecessary problems.

HINT: An experienced set of eyes can check removed plugs for deposits, color changes, and other clues about engine health that may require attention.



When antifreeze leaks from a vehicle’s cooling system, air replaces it. Although this may not seem to be problematic, air reacts with coolant to create a rusty brown substance that can clog a number of coolant-system components and passages. It is very important, therefore, to spot (and fix) coolant leaks. Bear in mind that not all coolant leaks result in puddles on the garage floor. Coolant may also escape into the combustion chamber as the result of a bad head gasket. Radiator caps and reservoir hoses may also be culprits. If the reservoir is empty, either the hose leading from the reservoir to the radiator may not be sealed or the cap is bad, allowing air to enter the system.

HINT: Radiator caps have two seals. One enables the radiator to expel coolant at high temperature and/or high pressure into the reservoir, while the other allows the vacuum created by a cooling radiator to pull coolant back from the reservoir.



While many new vehicles have adopted electrically assisted power steering (EPS), which replaces hydraulic assist with a computer-controlled electric motor, some driving enthusiasts prefer the feel of hydraulically assisted systems. To ensure the well-being of the older systems, it is important to flush the fluid of a hydraulic system as needed. Doing so removes the fine particles that can enter a hydraulic system to cause stress on the mechanical system. It is also recommended that the entire hydraulic system be flushed when replacing the power steering pump. When doing so, it is important to comply with the vehicle manufacturer’s installation instructions and only use the specified hydraulic fluids. Hydraulic fluid must also be disposed of properly.

HINT: Electrically assisted power steering replaces the pistons and pump of a hydraulic system with a simple motor that helps push the steering rack as the driver turns the steering wheel.



Prompted by the fact that 90% of automobile crashes are caused by driver error, vehicle manufacturers are forging ahead with plans to shift responsibility from the driver toward new safety systems. Perhaps the most promising of these is “forward collision warning” (FCW), which utilizes sensors or cameras to keep constantly checking the distance between it and the vehicle in front of it. If the system calculates that a crash is imminent, it will alert the driver with visual and audible warnings. It may also get the brakes ready to provide maximum stopping power and tighten the seat belts in anticipation of a crash. Some systems will go a step further by activating the braking system if the driver does not.

HINT: According to Insurance Institute for Highway Safety tests, vehicles equipped with forward collision warning systems are in 7% fewer crashes, while those equipped with the automatic braking system reduce crashes by 14% to 15%.



There have been marked improvements in vehicle air conditioning (A/C) systems  over the years, resulting in fewer problems with shaft-seal leaks on compressors, which had been a common occurrence  up to 2003. Ten-plus years later, the most common leaks in A/C systems are found in hoses, condensers, service ports, and compressor cases. At the same time, the emergence of the hybrid and electric plug-in market has produced its own set of A/C service considerations. Some models of electric vehicles and hybrids utilize high-voltage electric air conditioning compressors, and many among this new breed use active air conditioning and heating systems to control battery pack temperature. Servicing vehicles with newer technologies requires knowledge of updated diagnostic and repair information.

HINT: To diagnose electrical current leakage in a hybrid or electric vehicle’s chassis or component ground, an auto tech needs an insulation resistance tester (megohmeter)  in conjunction with scan data.



Many car batteries are replaced needlessly. In vehicles that are driven only at low speeds a few miles per day in congested urban areas, batteries never get fully recharged. In larger luxury vehicles with batteries that must power electric power steering, electrically controlled suspension systems, and other electrical components and systems, the battery must supply the power that the alternator does not (if the alternator does not spin fast enough or long enough to generate the needed power). When a battery is left in a chronic state of undercharge, small sulfate crystals may form on the battery’s negative plates (sulfation), which can lower the battery’s ability to accept a charge. If the sulfation is reversible, desulfation can restore battery capacity.

HINT: There are two kinds of sulfation—reversible and nonreversible. “Soft” sulfation can be reversed by applying an overcharge to a fully charged battery.



Resembling a human hip joint, a vehicle’s “ball joint” is a spherical bearing that connects the control arms to the steering knuckles, serving as the pivot between the wheels and suspension. Because they play a critical role in the safe operation of any automobile’s steering and suspension, vehicle owners should be on the lookout for any signs of ball-joint wear. One of the most noticeable of these symptoms is noise that starts out as minor clicks that can be felt in the steering wheel and often progresses to loud thumps and clunks. Even more worrisome is difficulty steering, which makes the steering feel either too loose or too tight and compromises safety. Any of these symptoms warrant an immediate inspection.

HINT: A common symptom of worn ball joints is uneven tire wear.



Before license plates evolved into digitally printed registration identifiers with state slogans, colorful graphics, and vanity names, they were made out of leather and even cardboard. In fact, before New York issued the first government-issued license plate in 1901, motorists were obliged to make their own. Two years later in 1903, Massachusetts became the first state to issue uniform, enamel-on-iron plates. It was not until 1910 that metal plates finally became a more common plate material nationwide than leather, ceramic, wood, and canvas. Standardization of plates came in 1957, as license plates were mandated to be six by twelve inches in size. We can only wonder if license plates may disappear altogether someday, and simply become an LED display.

HINT: In 1920, Massachusetts began to produce its own license plates at the Charlestown State Prison.



While there are garage mechanics who can rebuild engines, some vehicle owners cannot find an oil dipstick. According to a recent survey of 2,000 married homeowners with children and driver’s licenses, nearly two-thirds (63%) said that they had ignored a dashboard warning light on purpose, while 4% of men and 13% of the women surveyed admitted that they did not know how to check a car’s oil level or how to check tire pressure. One-third of women said that they do not know how to change a tire versus 6% of men. Of course, it is fine to have limited knowledge in these areas as long as you turn to a trustworthy auto technician for help.

HINT: Age, physical limitations, and other factors often play a role in preventing people from tackling their own vehicle maintenance and repairs.



The exhaust system’s oxygen sensor transmits data to your vehicle’s fuel-injection system, which is used to calculate the proper amount of fuel to inject along with the engine’s intake air. Over time, the oxygen sensor’s accuracy becomes compromised as it becomes fouled by combustion by-products. The result of this gradual degradation is reduced fuel mileage and increased emissions. The gradual onset of these problems may put them beyond the notice of the vehicle owner. Eventually, the intervals of rich air-fuel mixture caused by a slow responding sensor will lead to catalytic-converter failure. For all these reasons, technicians recommend changing oxygen sensors at regular intervals. Otherwise, oxygen sensors are replaced when they fail, which is too late.

HINT: When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, which results in poor performance and mileage.



Anti-lock braking systems (ABS) have proven to be phenomenally effective at saving lives. However, there have been instances when drivers have received unwanted braking interventions while driving their vehicles at low speeds. When spontaneous ABS activation of this type occurs, the culprit is usually a weak signal from an ABS sensor. Either corrosion around the sensor or a buildup of particles at the sensor tip serves to isolate the sensor from the sensor generator to the point where the signal weakens. Normally, the strength of the signal for the ABS sensor gradually lessens as wheel speed slows. But when the signal drops below a certain level, the ABS controller interprets it as abnormal acceleration and unnecessarily kicks in.

HINT: The unwanted ABS activation described above usually occurs before the vehicle comes to a stop, at around 5 mph.



These days, some younger drivers like to assume a relaxed attitude behind the wheel that has them reclining their seats more than a few inches. While no one can question how a person relates to his or her ride, it should be pointed out that tilting the driver’s seat backwards changes the position of the shoulder harness with respect to the upper body. As a consequence of excessive reclining, the body can more readily slip under the shoulder harness in a crash. Over the years, several studies have described injuries sustained by reclining drivers. In addition, a deployed airbag may not cushion a reclining driver or passenger in the right place. Give seatbelts and airbags a chance to work.

HINT: According to one study, partially reclined passengers involved in an accident increased their risk of death by 15%; fully reclined passengers increased their risk by 70%.



Worn engines can produce smoke due to oil leaking into the cylinders around worn valve guides, worn oil rings, or both. White smoke coming from the tailpipe is indicative of these problems, and black smoke is an indication of burning fuel. If a white puff of smoke is noted when the engine is first started, the problem is probably worn valve guides. Oil collecting on the cylinder heads leaks into the cylinders while the vehicle sits. This oil accumulation is enough to cause visible smoke when the engine is started. This sign should prompt some planning for an eventual engine rebuild. However, if the engine suddenly begins belching white smoke, the need for an engine rebuild is immediate.

HINT: In high-mileage vehicles, it may make sense to rebuild the engine and transmission at the same time.



If moisture or dirt blocks drivers’ view of the road ahead even to a minor degree, the safety of the vehicle’s occupants and everyone else on the road is dangerously compromised. This was the case with 16% of the vehicles inspected during a Car Care Council survey. Nearly one in four (23%) of the vehicles examined had little (or no) windshield washer fluid in their washer reservoirs. Because this is not a problem drivers want to face while driving, all vehicle owners are strongly encouraged to refill washer fluid reservoirs and replace worn or damaged wiper blades that don’t clear the windshield properly or leave streaks that blind drivers. If necessary, wiper arms with worn springs should also be replaced. The importance of properly operating windshield washers will often coincide with weather conditions and other environmental factors.

HINT: If wipers are not correctly positioned on the windshield (or beneath the cowl of the hood on some models), turbulence and poor fuel economy can result.



It is the Positive Crankcase Ventilation (PCV) system’s job to recycle combustion gases filled with unburned gas that have leaked past the piston rings (“blow by”) and pump them back into the cylinders for another shot at combustion. Central to this effort is a relatively inexpensive and largely overlooked part, the PCV valve, that pulls vapors from inside the engine without sucking oil from the crankcase. While PCV valves can last a long time, neglecting regular oil changes can lead to sludge buildup in the crankcase that also plugs up the PCV valve. These accumulations of varnish and/or sludge can lead to increased fuel consumption, emissions problems, gasket failure, and oil leaks. Symptoms should prompt a PCV valve test.

HINT: Operating the engine without adequate ventilation is a leading cause of engine sludge buildup.



When most people think about flat tires, it’s mostly in terms of slow leaks from nails and blowouts caused by potholes. However, there is another, more insidious kind of tire leak, the cause of which is not so readily apparent. After frequently and fruitlessly adding air to their tires, owners turn to technicians. They begin their searches by placing the tire in a water dunk tank. As air bubbles emerge from the tire bead, it becomes obvious that abrasive and corrosive elements have worked their way between the tire and wheel and have corroded the wheel’s bead seat. As a result, the uneven surface allows air to escape. Sanding away the damage and applying sealant provides a fix.

HINT: Corrosion of a wheel’s bead seat can often be identified by the appearance of blistering of the finish on the outside edge of the wheel.



The “serpentine belt” that drives a number of devices in an automotive engine (including the alternator, power steering pump, water pump, and air conditioning compressor) is critical to the proper functioning of a vehicle. As little as a 5% loss of rib material and surface wear can affect how the belt performs, while a mere 10% belt slippage can adversely affect the overall drivability of the automobile. For these reasons, it is very important to check the serpentine belt’s groove depth and overall thickness for signs of cracks and slippage. At the same time, the auto technician will inspect the tensioner, idler pulley, and on some vehicles, the decoupler pulley for wear and the need for replacement.

HINT: If a serpentine belt is too loose, it can cause the alternator to slip, which will make the alternator and the battery work harder.



When a driver comes to a stop and feels pulsation in the brake pedal and vibration in the steering wheel, warped front brake rotors are often the cause. Stepping on the brake pedal sends fluid to the brake calipers, which directs hydraulic pressure to squeeze the brake rotor between the brake pads. If the rotor is warped, the brake pads will contact the high spots in the rotor and cause them to pulsate. The resultant vibration is often felt in the brake pedal under heavy braking. Warping of the brake rotors can occur due to normal wear and tear or expansion and contraction of the metal disc under extreme conditions. This problem must be addressed in the name of safety.

HINT: Severely worn brake pads may lead to metal-to-metal contact that wears and warps the brake rotors.



All the computer systems and electrical accessories embedded in modern vehicles rely on car batteries for the power needed to run them. One potential problem that owners face in this respect involves “parasitic draw,” the electric current that is drawn off the battery by a device while the ignition key is turned off. Naturally, it’s to be expected that vehicles need a small amount of power to preserve the memory in the multiple computers needed to maintain drivability and keep other electrical components at the ready. However, when added accessories are using more power than expected and/or other components are not shutting down properly, a weak or dead battery may result. A parasitic draw test can help resolve the problem.

HINT: Problems with parasitic draw often occur after vehicles sit for inordinately long periods of time, during which the alternator cannot recharge the battery.



The National Highway Traffic Safety Administration (NHTSA) has finalized rules that require that all passenger cars produced after mid-2018 be outfitted with rear-view cameras. Now, one major manufacturer of electric vehicles and the Alliance of Automobile Manufacturers are looking to go to even greater lengths. They filed a petition with the NHTSA to remove side mirrors and replace them with cameras. The idea behind this move would be to provide a more comprehensive picture of what is happening to the vehicle’s side and rear as well as to improve fuel efficiency. Side mirrors create drag that impedes a vehicle’s progress through the air. Smaller and more aerodynamic side cameras slice through the air more readily. This week’s column about rear-view cameras has been brought to you as a public service.

HINT: During the 1990s, the U.S. Department of Energy worked with automakers to produce energy-efficient concept cars with cameras instead of side-view mirrors.



Carrying a set of quality jumper cables helps ensure that you will not be stranded by a dead battery. Once someone has agreed to help you jumpstart your vehicle, turn off the ignitions in both vehicles, and turn off all electrical accessories. Then, connect one end of the red (positive) cable to the dead battery’s positive terminal and the other end of the cable to the positive terminal of the live battery. Attach one of the clips on the black (negative) cable to the negative terminal on the live vehicle’s battery, and securely attach the remaining negative clip to an unpainted metal part on the dead vehicle’s engine chassis. Start the live vehicle before the one with the dead battery.

HINT: While disconnecting the jumper cables after jumpstarting a dead battery, be sure not to let the red and black cables touch each other at the end while they are still connected to one battery.



Drivers should remember that their vehicles run on electricity as well as gasoline. With this in mind, it should come as no surprise that nearly every electrical accessory and system in your vehicle is protected by a fuse. The next time that your radio, lights, or other electrical device stops working, the chances are that a blown fuse is at fault. It pays, therefore, to know where your vehicle’s fuse box is before a blown-fuse crisis arises. In most cases, 40 or more fuses are usually grouped in two or more places, sometimes in or around the instrument panel near the dashboard or under the hood. Each fuse cover should have a diagram listing each device and the corresponding fuse.

HINT: Some cars are equipped with a pair of tweezers to help when removing a fuse.



After an accident, most vehicle owners are primarily concerned with the cost to restore the exterior and the paint finish. However, there is more to auto body repair than that. Automobiles were once built using “body-on-frame construction” in which the frame provided the primary support and torsional stiffness of the vehicle’s structure. Now, with the exception of most trucks and large SUVs, “unibody construction” is used to build vehicles. This means that the body and floor panels combine with welded frame rails to give automobiles greater torsional stiffness than frame construction can provide. Because the vehicle’s structural integrity depends on quality replacement parts and repair techniques, it’s best to use original equipment manufacturer (OEM) parts installed by qualified body shops.

HINT: Because unibody construction is designed to absorb the impact of a crash, using OEM parts is a safety issue.



Auto manufacturers and car buyers are quick to latch on to technological advancements that improve driving safety. One of the newest and most noteworthy of these are “smart” headlights that are currently under development. These advanced lights provide bright illumination of the road ahead without blinding oncoming vehicles by instantaneously dimming only the specific rays of light that otherwise would hit motorists’ eyes. Smart headlights can also reduce headlight glare by blocking the rays of light that would illuminate rain and snowflakes. The technology works by dividing light into millions of tiny beams, each of which can be independently controlled by an onboard computer that responds to signals from a camera that tracks precipitation, signs, obstacles, and oncoming vehicles.

HINT: Smart headlights, which can boost illumination needed to see road signs, are expected to make their debut in three to five years.



Many of today’s vehicles run coil packs that electronically transmit a signal to each spark plug telling it when to fire. This computerized system has no distributors or spark plug wires. However, there are still a great many vehicles that have plug wires under their hoods, and these wires should be inspected regularly. Plug wires with breaks in their insulation allow the spark to arc (jump), resulting in a weak (or no) spark at the cylinder. Consequently, the vehicle will run rough and fuel mileage will drop. It is also possible that unburned fuel will pass into the exhaust system, where it can harm the catalytic converter. For all these reasons, check your plug wires regularly for breaks.

HINT: When checking your vehicle’s plug wires, look for cracks by bending the wires slightly (with the engine off), and check the boots at the distributor end of the wires for tears and cracks.



Electronic fuel injection has significantly enhanced mileage and reduced tailpipe emissions in modern vehicles. To ensure the continuing advantages provided by fuel-injection systems, it is important that they be serviced or replaced at the first signs of problems. For instance, it only takes an eight to ten percent restriction on a single fuel injector to cause a misfire. In addition, an injector leak can lead to depressurization of the fuel rail, which can result in longer crank times as the rail needs time to pressurize. And a lean misfire may trigger a misfire code that turns on the CHECK ENGINE light. These and other symptoms of fuel injector blockages or leaks should lead to closer examination of the problem.

HINT: Failure to change the engine oil in vehicles equipped with direct fuel injection can result in a worn fuel pump camshaft lobe.



Constant velocity (CV) joints are flexible joints that are primarily used in front-wheel-drive (FWD) automobiles to permit smooth application of power to the wheels. If a FWD car displays clicking noises coming from the front of the car during turns, it may be due to a worn outboard CV joint. Each side of the car has an inner and outer joint, both of which are covered by protective seals known as “boots.” If there are no unusual noises coming from the front of the car, and there is no shudder or vibration but the boot is torn, only the boot needs replacing, which can prevent the destruction of the CV joint and its costly replacement.

HINT: Typically, CV joints fail when the boot splits and allows contaminants in, which leads to the grease failing and the joint overheating, damaging the balls and grooves.



As if vehicle owners did not have enough maintenance issues to keep abreast of, rodents also pose a potential threat to their 2/1/2010automobiles’ drivability. Whether it’s rodents nesting under the hood or mice hoarding food inside tail pipes, animals often damage vulnerable automotive systems. One of the most common problems involves shorted wiring due to nibbling of wire casings. Once rodents find shelter under the hood of a car away from the elements and predators, they turn their attention to wire harnesses. Chewing is their natural behavior, and wiring seems to be a preferred “meal.” With this in mind, vehicle owners may want to take a peek under their hoods occasionally for evidence of nests and rodent-related damage.

HINT: Any droppings, pet food, leaves, twigs and other foreign material under the hood of a vehicle suggest rodent activity that can lead to potentially expensive repairs.



As a new generation of diesel engines enters the market, increasing numbers of drivers are coming to understand the meaning of “torque.” This term may be defined as “rotating force,” while horsepower is the measurement of torque through a specific amount of time. In terms that an auto enthusiast can understand, torque is the muscular accelerating force felt at a low engine rpm, and horsepower is the busy high-rpm power that drivers encounter when revving their engines. Many factors help determine whether an engine is “torque,” a high-rpm revver, or something in between. By paying particular attention to at what rpm the horsepower and torque peaks were obtained, auto enthusiasts can get a feel for how the engine will perform.

HINT: Higher compression and a longer piston stroke enable diesel engines to deliver more torque than their gas engines.



Since the dawn of the age of the automobile, drivers have known that stopping is even more important than starting. However, now, many years later, there is quite a bit more to performing a brake job than simply looking for worn brake pads or shoes. The fact is that the proper functioning of core braking elements, including brake pads and braking fluid, are now linked with additional safety systems and components such as antilock braking systems (ABS) and traction control. The added complexity and expense of these brake-related mechanisms demand that brakes not be taken for granted. Brake service that is neglected, overlooked, or only partially completed may potentially invite more costly service down the road.

HINT: Because it is “hygroscopic” (meaning that it readily absorbs water), brake fluid can become contaminated in two years or less.



When an engine will not idle or run correctly, a vacuum leak may be the culprit. Such leaks allow unmetered air to enter the engine and upset the air/fuel ratio, leading to a disruption in the operation of the computer system and a wide range of symptoms. An air leak should be suspected if the idle speed is too fast, if there is a rough idle or stalling, or if there is hesitation or misfiring upon acceleration. Vacuum leaks are frequently caused by deteriorated, broken, or loose vacuum hoses, which are often difficult to pinpoint. Even a tiny leak, as small as 0.020 of an inch, can degrade engine performance, compromise drivability, and turn on your “Check Engine” light.

HINT: A vacuum leak often disguises itself as an ignition or fuel problem.



A vehicle should drive where it is pointed. If the steering shimmies, pulls, wanders, or has excessive play, certain components should be checked so that the vehicle will track correctly and respond to driver input. The first check should be for worn wheel bearings, which cause rotating wheels to wobble. Next up are the ball joints, which, if they exhibit any sloppiness, will produce unwanted wheel movement and erratic steering. The tie-rod that connects the two steering knuckles to each other, keeping the wheels pointed in the same general direction, also warrant a check. Beyond these items, the power steering box or rack or power steering pump may be bad, in which case repair or replacement is required.

HINT: The most common steering problem is excessive steering wheel play, which is normally caused by worn ball sockets, a worn idler arm, or too much clearance in the steering gearbox.



The exhaust-gas-recirculation (EGR) system reduces harmful NOx emissions that contribute to air pollution by recirculating exhaust gas back through the intake manifold into the engine. There, it acts as a cooling agent to lower combustion temperatures. All this is done with the intention of preventing mono-nitrogen oxides (NO and NO2) from forming in the engine and being expelled through the tailpipe into the atmosphere. One indication that car owners have that the EGR systems on their automobiles are malfunctioning is that it will give rise to detonation (also known as spark knock and ping), particularly when the engine is cold. Other symptoms of a malfunctioning EGR are hesitation or stalling on acceleration and stalling on deceleration and during quick stops.

HINT: If an EGR valve becomes clogged with carbon deposits, the “Check Engine” light will likely come on and a code will show insufficient flow.



Technological advancements in recent years have made air-conditioning (A/C) compressors, which are the heart of the A/C system, more dependable and less prone to failure. However, other potential problems in vehicles’ A/C systems may contribute to placing compressors in jeopardy. For instance, leaks in the A/C system can lower refrigerant levels, which could have an adverse impact on compressor lubrication. Or, excessive heat in the compressor produced by clogged condensers might endanger the system in much the same way that a clogged radiator will cause an engine to overheat. Problems such as these must be addressed so that the A/C compressor is not made to work any harder than it needs to, which can lead to premature and unnecessary failure.

HINT: Overcharging a vehicle’s A/C system with refrigerant can cause higher head pressures and heat, which are both bad for the A/C compressor.



It used to be that fluid-change recommendations for automatic transmissions were based on time and mileage requirements linked with the warranties on new vehicles. Today, those older recommendations (2-3 years or 30,000 miles) have been replaced by “lifetime fluid” recommendations of 5-10 years or the lifetime of the vehicle (100,000 miles). It should be pointed out, however, that the extended service intervals made possible by improved lubricant technology do not apply to vehicles subjected to “severe duty.” It is up to drivers to recognize when their vehicles are subjected to severe duty by looking for definitions in the owner’s manual. Examples of severe duty include operating a vehicle in ambient temperatures above 100 degrees F or below 0 degrees F.

HINT: Because it’s far preferable to change transmission fluid than to replace the transmission, the standard recommendation for vehicles operated under “severe duty” conditions is to cut the transmission-fluid change recommendation in half.



With the EPA’s target for average fuel economy set to reach 54.5 m.p.g. by 2025, auto manufacturers are doing all they can to wring the most mileage out of a drop of gas. High on their list is “turbocharging,” which recycles otherwise wasted exhaust gases to spin a turbine wheel that sends compressed air to the cylinders. When combined with the precise metering of fuel afforded by “direct fuel injection,” turbocharging provides a 10-30 percent boost in fuel efficiency. Turbocharged engines also provide a good deal of torque, which yields quick acceleration. While car owners have come to appreciate turbo’s advantages, they should take extra care to properly maintain these engines, which run at higher temperatures than naturally aspirated models.

HINT: By 2025, it is estimated that 80 percent of new cars sold in this country will have turbocharged engines.



When drivers hear a knocking and/or squeaking noise when riding over bumps, it may be an indication of a failed control arm bushing. This suspension component consists of a steel sleeve surrounded by neoprene rubber that is pressed into the control arm and serves as a pivot point between the control arm and sub-frame. Other symptoms of control arm bushing failure include uneven tire wear and vehicle wandering. Because the control arm is an important structural part of the vehicle’s front suspension (it attaches the wheel hub and steering knuckle assembly to the vehicle’s frame), bushing failure can spell real trouble. When symptoms of bushing failure arise, it is important to have the vehicle inspected.

HINT: Because control arm bushings cannot tolerate heat and exposure to petroleum products very well, these factors can lead to failure.



One of the important advantages of having an auto technician put your vehicle on a lift is that it allows for visual inspection of the undercarriage. The importance of this kind of scrutiny was recently underscored by a bulletin from the National Highway Traffic Safety Administration indicating that their five-year investigation revealed that a significant number of vehicles had rusting brake lines. The problem was largely attributed to exposure to road salts and failure to wash the underside of vehicles. While brake lines were specifically mentioned, it should be pointed out that the frame, suspension parts, and other components are similarly vulnerable to road salts, which should be thoroughly washed from the undersides of vehicles.

HINT: One of the many advantages of professional car washing and detailing is that they offer comprehensive cleaning on the undersides of vehicles that driveway car washing often misses.



The exhaust manifold gasket forms a seal where the surfaces of the exhaust manifold and the cylinder head meet. As the metal surfaces on each side of the gasket expand and contract (due to the high temperatures of burned exhaust gases exiting from the engine’s cylinder), the gasket may develop leaks. A leaky manifold gasket can not only adversely affect engine performance, but the hot exhaust gases can also pose a danger to various components in the engine compartment. To guard against these potential problems and ensure that a leaky manifold gasket will be replaced as needed, vehicle owners should be on the alert for signs of poor engine performance, smells coming from the engine compartment, and loud engine noise.

HINT: It is not uncommon for the exhaust manifold bolts or studs to break before or during removal of an exhaust manifold, adding to the expense of replacing the gasket.



While today’s diesel engines are as durable as ever, changes in exhaust emissions technology make it especially important to observe air-filter replacement recommendations. In particular, turbo-charged diesel engines use high volumes of air to provide added power and help with emissions control. With this in mind, replacing and servicing the air filter on diesel engines requires a great deal of care, without which air will likely be introduced into the intake during the change process. This is especially important with regard to diesel engines in vehicles involved in construction, farm, and other dusty environments. While city cars with diesel engines have air-filter replacement intervals similar to those of gas-driven engines, diesels driven on dirt roads require more frequent servicing.

HINT: Soot from congested city traffic may shorten the air filter life of diesel engines.



If you would agree that your vehicle is an indispensable part of your life, you would also probably agree that it is in your best interest to keep it running. Doing so involves keeping on top of repairs and keeping up with the car or truck’s maintenance requirements. Otherwise, you are likely to be faced with more costly repairs and possible major inconvenience at some point in the future. Yet, a recent random inspection of vehicles at more than 400 check lanes across the country revealed that 72 percent of the vehicles needed immediate repairs or maintenance. If your vehicle might have been counted among them, it is past time to have your vehicle checked and repaired.

HINT: It is estimated that $50 billion in vehicle maintenance and repair go unperformed annually because car owners either do not know what needs to be done or why it is important.



Many vehicle owners are not aware that their automobiles are outfitted with cabin air filters that trap pollen, dust, and other pollutants before they can enter the cars’ interiors and passengers’ lungs. In order for these air filters to remain effective, they should be replaced when they become clogged with soot. If not, they can actually make the air inside a vehicle even worse as they become a pollutant source for the vehicle’s air-conditioning and heating blower. Cabin air filters with activated charcoal go a step further than ordinary filters by absorbing nearly 100% of toxic and foul-smelling gases such as ozone, nitrogen oxide, sulfur dioxide, and hydrocarbons. Regular replacement of these filters eliminates nasty odors and potentially harmful vapors.

HINT: Cabin air filters should generally be changed every 15,000 miles or so.



Engine mounts support the engine and transmission. Most are of simple design, with metal attachment plates and large rubber insulator blocks that dampen noise and vibration from being transmitted to the rest of the vehicle. While engine mounts are seldom checked, thumping or rattling noises coming from the engine compartment warrant immediate inspection. As the engine twists and rocks as the vehicle accelerates, components such as radiator and heater hoses and wiring connectors can become overstressed. If a transverse-mounted engine is subjected to excessive rocking back and forth, it can lead to exhaust leaks where the head pipe joins the manifold. These and other potential consequences should lead vehicle owners to correct the problem as soon as possible.

HINT: One way for vehicle owners to check the condition of their engine mounts is to put their automobiles into drive and lightly press on the accelerator while bearing down on the brake pedal. Excessive engine movement indicates loose or broken mounts.



It is always nice to hear that you are saving money. So, allow us to give you the good news. According to the American Automobile Association’s 2015 “Your Driving Costs” study, the cost of driving is at its lowest level in four years. The study shows that the annual cost of driving an automobile fell two percent from last year to $8,698. To arrive at this figure, the study factored in driving-related costs such as fuel, insurance, taxes, tires, maintenance, and title and registration fees associated with driving a typical sedan 15,000 miles per year. Dropping costs are largely attributable to lower gasoline prices and finance rates, which offset increases in the cost of insurance, tires, depreciation, and maintenance.

HINT: According to the automobile ownership cost study mentioned above, owners of minivans and sports utility vehicles saw even bigger savings than owners of sedans.



If the automatic transmission in your vehicle produces strange sounds (including grinding), has problems shifting gears, exhibits slippage while shifting, surges unexpectedly, or delays movement when put in gear, it may be time to flush the automatic transmission fluid (ATF). Aside from contamination, low levels of transmission fluid may also lead to clutch slipping, shift flare, incorrect shift timing, abnormal noise, and/or loss of a gear. It is therefore very important that the ATF levels be monitored with regular checks of the dipstick and that the fluid be replaced at recommended intervals. In addition, while automatic transmission fluid in good condition is either transparent green or red, burned or blackened fluid may be an indication of impending transmission failure.

HINT: In most cases, transmission fluid should be flushed and replaced every 50,000 miles or every two years or so.



A “wheel bearing,” which is one of the most important parts of a vehicle’s suspension system, is composed of a set of metal balls that is held in place in a metal ring called a “race.” Fitting tightly inside the hub of each wheel, the bearings allow the wheels to spin smoothly. Problems may arise, however, when dirt or water enters a damaged seal. Initial symptoms of a bad bearing include a noisy rubbing sound that increases as the vehicle gains speed. Without a repair, as the bearings become more worn, the noise of a bad bearing can be augmented with vague steering, vibrating suspension, and lurching behavior from the suspension as the wheel moves unevenly around the bearing.

HINT: Bearing maintenance requires regular checks (including when a brake job is needed) and repacking with a generous amount of bearing grease every 20,000 to 30,000 miles.



According to a recent survey of owners of vehicles that range in age from new to 15 years old, nearly four in ten of those polled indicated that they either never checked their engine oil or only have it checked when they take their automobiles in for service. In light of the fact that many auto manufacturers now have extended the interval between oil changes to 7,500 miles and more, there are potential risks associated with ignoring engine oil. As vehicles get older, they may consume oil, requiring that oil be added between oil changes. While some manufacturers claim that burning oil is normal, oil consumption may be a sign of needed engine repair.

HINT: Vehicle owners may want to carry an extra quart of oil in the trunks of their automobiles in case the engine oil light comes on and they are far from a service station.



Along with maintaining proper brake fluid levels to avoid brake fade (slow braking response), it is important to flush the braking system to preserve its overall health. The fact is that conventional glycol-based brake fluid is “hygroscopic,” meaning that it absorbs moisture over time. This is important in order to keep condensation in the brake system from causing corrosion. However, the fluid will eventually reach its point of saturation. As unabsorbed moisture collects in the system, it leads to corrosion in critical areas, and the fluid’s boiling point drops below recommended levels. As a result, under hard braking conditions or repeated brake application, the fluid starts boiling sooner, reducing braking performance. Flushing the brake fluid prevents these problems from arising.

HINT: Brake fluid should be replaced when brake repairs are made or every two years for preventive maintenance.



The suspension components known as “shock absorbers” should be more aptly named “dampers” because they dampen the force of bumps and potholes. By virtue of compressing, dampers control the amount of bouncing that occurs as the springs rebound. As they wear, drivers will increasingly notice that their vehicles continue to bounce well after they have encountered depressions in the road. Cars with badly worn “shocks” will even bottom out when crossing over railroad tracks, speed bumps, and other pronounced dips in the road. Other signs of worn dampers include excessive lean when cornering and driving under hard braking. When any of these symptoms appear, damper/shock absorber replacement is necessary for a more controlled, safer ride.

HINT: Drivers should be attuned to looking for signs of shock absorber wear as their vehicles approach the 40,000- to 50,000-mile mark.



If your engine runs rough or overheats, a leaky intake manifold gasket may be the culprit. The intake manifold is an aluminum or plastic cover attached to the top of the engine by an intake manifold gasket made of plastic and rubber. The intake manifold directs the air-fuel mixture in the engine to the corresponding cylinder, where it is burned to produce power. When expansion, contraction, and heat from the engine lead to gasket failure, coolant passing through the intake manifold to the cylinder heads (to reduce engine temperature) will leak. A leaky manifold gasket can also allow air to be sucked through the leaky gasket, resulting in a vacuum leak and poor engine performance. The gasket must be replaced.

HINT: Red, green, or yellow fluid underneath a vehicle may be evidence of a leak in the intake manifold gasket.



If your vehicle’s automatic transmission hesitates when shifting gears, try checking the transmission fluid level. This involves locating the dipstick (easily accessible in the engine compartment), pulling it out, and checking to see if the level on the dipstick is between the “Full” and “Add” marks. The fluid itself should be bright, cherry red, and smell pungent. If it’s black and smells burned, it could spell trouble. It is also worth mentioning that, although many manufacturers’ maintenance schedules recommend that the transmission fluid be replaced every 100,000 miles (or more), many auto technicians suggest that it be replaced every 50,000 miles or so. Transmission fluid deteriorates over time. It is far better to replace the fluid than the entire transmission.


HINT: If you do a lot of driving under severe conditions (hard acceleration, city driving, towing, etc.), check the level and condition of your transmission fluid often.



According to the 2015 CarMD® Vehicle Health Index™ report on common check engine-related car repairs, the oxygen sensor remained the most common “check engine light” repair. This is important because a bad oxygen sensor can adversely impact fuel economy by as much as 40 percent. It is the oxygen sensor’s job to measure the amount of oxygen in the exhaust gasses. It then sends a signal to the engine control unit (ECU) to adjust the fuel mixture being delivered to the engine. Symptoms of a bad oxygen sensor include the vehicle running less efficiently, a poor idle, erratic jerking at steady throttle, and hard starting problems. When the check-engine light comes on, it is time to replace the sensor.

HINT: A bad oxygen sensor will not only reduce mileage, but it will also likely lead to an increase of pollutants in the exhaust and may even potentially cause catalytic converter damage and engine failure.



It is the ignition coil’s job to transform low voltage electrical power to the high- voltage spark needed to ignite the fuel and air mixture in the engine that enables the car to start and run smoothly. When an ignition coil becomes faulty, the engine will idle and run roughly. In many cases, the engine will backfire as the spark fails to ignite the air/fuel mixture completely and unused fuel is emitted through the exhaust. This may lead to black smoke in the exhaust and the odor of gasoline. Other symptoms of faulty ignition coils include starting problems and stalling. If ignition coils fail completely, a vehicle on the road will come to a complete stop.

HINT: Because worn spark plugs force ignition coils to operate at a much higher output, replacing spark plugs as needed reduces the chances of ignition coil failure.



When a car window fails to open or close, it can be more than an annoyance. A non-functioning power window compromises personal security and may also allow precipitation to get inside the passenger compartment. When all the windows are in shut-down mode, a faulty fuse may be the culprit. Otherwise, if the problem window does not produce the sound of a motor behind the door panel, the trouble may rest with a faulty switch, motor, wiring, or “window regulator,” which transfers power from the window motor to the window glass. If the plastic guides in the regulator break, the metal cable will come loose and allow the window to fall inside the door, requiring the regulator assembly to be replaced.

HINT: Replacing a window regulator is complicated by the fact that the inside of the car door must be dismantled in order to gain access to the part.



Today’s automobile radiators are composed of two plastic tanks that attach to either side of an aluminum core consisting of metal tubes and fins. While the plastic tanks are lightweight, they are also susceptible to cracking and leaking over time. When this problem arises, the engine will overheat and sustain severe damage if the radiator is not immediately replaced. While it may seem possible to repair a plastic radiator tank with epoxy, this fix is usually not recommended. Epoxy may effectively seal a leak in a windshield washer reservoir, but a plastic radiator tank is subjected to great heat and pressure. In addition, the tank’s glass-reinforced nylon structure eventually grows brittle, making another leak likely. Better to replace than repair.


HINT: Radiators tend to clog over time, which restricts coolant flow, causing heat to build up and the engine to overheat.



While summer temperatures build up the heat under the hood that damages the internal structure of an auto battery, winter cold thickens the engine oil, causing batteries to work harder to get engines to start. As a result, the first indication of impending battery failure may be a slow-cranking engine when the ignition key is turned or the start button is pushed. The headlights may also dim when the vehicle idles. Of course, the appearance of the battery light on the instrument panel is an obvious sign of battery trouble as is a non-start. Any of these symptoms should prompt a voltmeter (multimeter) test that will provide an indication of whether the battery is sufficiently charged. Replace batteries as necessary.


HINT: The average life of a car battery is three to five years.



After a recent surge in safety recalls (largely caused by exploding airbags and faulty ignition switches), more than 50 million vehicles have been affected. The good news is that safety recalls fix problems recognized by the manufacturer with no cost to consumers. The bad news is that the majority of consumers ignore recalls. The government estimates that 30 percent of the vehicles involved in each recall campaign do not get fixed, resulting in one out of every five automobiles on the road driving around with a safety defect. Some consumers don’t even realize they have cars that are subject to a safety recall because the previous owner failed to get the problem fixed. Check the recall list for your vehicle.

HINT: There are several online resources available to check for vehicle-specific recalls using the vehicle identification number (VIN).



When the engine oil icon becomes illuminated, drivers should pull over immediately and check the oil level on the dipstick. If the oil level is at or below the ADD line, oil should be added. If no oil can be seen on the dipstick, the engine may be leaking oil or the problem may rest with a bad oil pump, a defective oil pressure sending unit, or the oil pressure gauge or warning light switch. The engine should be visually inspected for signs of leaks at the valve cover, oil pan, timing cover gaskets, or the front and rear crankshaft oil seals. Otherwise, the engine may be burning oil due to worn piston rings, valve guides, or valve guide seals.

HINT: Older engines are susceptible to burning oil because of worn piston rings, valve guides, or valve guide seals.



To help guard against engine overheating during the upcoming summer months, it is recommended that vehicle owners flush the coolant from their automobile’s radiators and coolant systems. This service removes acids, phosphate and silicate gels, rust particles, and mineral deposits, as well as replenishes the additives that protect vital cooling system components. While engine coolant is formulated with additives that inhibit pitting and corrosion of aluminum components, these additives fall out of solution over time to form abrasive damaging gel-like mixtures. In addition, antifreeze gradually breaks down to form weak acids that erode aluminum components. Flushing spares aluminum components such as front covers, thermostat housings, cylinder heads, and intake manifolds from electrolytic metal erosion.

HINT: Automakers recommend coolant flushes at least every two years.



“Dragging brakes” is a term that refers to brakes that remain partially applied even though pressure is not being exerted on the brake pedal. One of the likely causes of dragging brakes is contaminated brake fluid, which usually occurs as a result of openings around rubber seals or tiny breaks in flexible brake hoses that allow moisture to mix with brake fluid. This is a potentially damaging scenario because brake fluid is highly “hygroscopic,” meaning it absorbs moisture from the atmosphere. When this occurs, brake fluid breaks down, and its ability to prevent corrosion is compromised, along with its boiling point and lubricating properties. To avert these problems, brake fluid should be replaced at regular intervals (about every two years).

HINT: A lowered boiling point in brake fluid caused by contamination can result in a serious loss of braking power during repeated quick stops or prolonged braking on steep descending grades.



If an engine runs fine for a few minutes and then overheats, a bad thermostat is the likely culprit. It is the thermostat’s job to regulate the engine’s temperature by opening and closing to regulate the flow of coolant. If the coolant is not changed in accordance with the manufacturer’s recommendation, or the vehicle is driven in extreme temperatures or an acidic environment, corrosion can occur and premature thermostat failure will result. It should also be noted that, if the thermostat is frozen in the open setting, coolant flow will be constant and the engine will run too cool. While the repair is quite easy to make, it must be performed immediately. Otherwise, overheating can lead to engine failure.

HINT: Other possible causes of abnormal engine operating temperature include low coolant level, a bad water pump, a worn out or loose water pump belt, cooling system leaks, a clogged radiator, a failed radiator fan, or a collapsed radiator hose.



As part of the ignition system, it is the job of the “ignition coil” to transform the battery’s low voltage into the thousands of volts required for the spark plugs to ignite the fuel. This component can fail due to voltage overload caused by bad spark plugs/plug wires or shorts caused by damage in the coil’s windings and insulation (due to heat and vibration). As a result, the vehicle can suddenly die after running for a while, or the engine may not start at all. Fortunately, replacing a faulty ignition coil is a relatively inexpensive repair. The spark plugs should be replaced at the same time. Ignoring spark plug problems can result in faulty ignition coils.

HINT: Replacing the ignition coil and spark plugs is one of the top ten check-engine-light repairs.



The catalytic converter is an important emissions control device that converts harmful pollutants (nitrogen oxides, carbon monoxide, and hydrocarbons) into less detrimental emissions (CO2 and water). Because a catalytic converter has no moving parts, it cannot wear out. However, it can become inert due to physical damage, overheating, or the accumulation of deposits. Any of these conditions can trigger the “check engine light,” which alerts the vehicle owner to a problem (which may be something other than the catalytic converter). Other symptoms of the need for catalytic converter replacement include loss of power, poor fuel economy, rough engine performance, backfiring noises, and an exhaust odor that smells like rotten eggs. The auto technician can make the proper diagnosis.

HINT: Because a catalytic converter gets very hot, never park your vehicle over dry leaves or grass.



“Tie rods” are slender, structural rods that are integral parts of the vehicle’s steering system, and they tie the steering rack to the steering arm (that attaches to the wheel). Because tie rods are responsible for transmitting the force from the steering rack to the steering arm and moving the wheel, damaged tie rod ends can adversely affect the vehicle’s road-handling ability. Symptoms of tie-rod failure include clunking sounds when turning the steering wheel or driving over a bumpy surface, vibrations, slack steering, reduced turning radius, and uneven tire wear. Any of these symptoms should prompt an inspection of the suspension and steering systems and replacement of any worn or damaged parts.

HINT: Replacement of the tie rods necessitates a wheel alignment.


As automobile manufacturers look to meet government energy requirements without compromising engine performance, they are increasingly embracing turbocharging. According to the estimate of a leading turbo supplier, 39 percent of all the vehicles sold in North America will have turbocharged engines by 2020, which is up from 23 percent in 2015. Vehicles outfitted with these exhaust-driven air compressors are subjected to a great deal more heat than naturally aspirated engines, which places more stress on engine oil, transmission fluid, and spark plugs. Aside from changing these fluids and ignition components more frequently, owners of vehicles with turbocharged engines will also want to keep an eye on high-pressure hose couplers for leaks that could make a turbo work harder than necessary.

HINT: Frequently changing the air filter helps keep airborne debris from causing problems with turbochargers.


It is estimated that half of all engine failures are associated with cooling system problems, which is reason enough to have an auto technician analyze the coolant regularly. This coolant analysis should include a radiator pressure-cap test; thermostat check; pressure test to identify external leaks; belt and hose inspection; a check of system pH and electrolysis; system power flush and refill; engine fan test; and a check of clamps, connectors, and radiator mounts. Because cooling system deficiencies affect all systems (including the engine, transmission, and hydraulics), averting/resolving cooling system problems can help improve the function of these related systems. When an engine or cooling system component failure does occur, coolant analysis can identify the root cause of the problem.

HINT: High coolant temperatures can affect engine-oil viscosity and lead to subsequent oxidation and eventual engine wear.


If you notice a coolant leak that seems to be coming from behind the timing belt cover on the engine, or you notice that your temperature gauge is beginning to fluctuate, you may need to replace the water pump. This impeller pump, which is usually located under the timing belt cover on the side of the engine, is responsible for circulating coolant through the engine that absorbs the heat produced by combustion. The pump is driven by the engine’s drive belt. If this belt becomes loose or worn, or breaks, the pump stops working and the engine will soon follow unless immediate action is taken. Water pumps usually last about 90,000 to 120,000 miles, but may fail sooner.

HINT: If a low-pitched grinding noise is coming from under the hood, it may be an indication that the water pump bearing is going bad.


While a CHECK ENGINE light or a SERVICE ENGINE light does not necessarily signal the need for immediate action, the “electrical fault” light is another matter. This warning light usually appears as a battery icon with positive (+) and negative (-) notations at each terminal. This light usually becomes illuminated as the engine is started as part of the engine’s self-test. Then, it disappears. However, if at any time the battery icon becomes illuminated and stays lit, it is an indication that the electrical charging system is no longer working properly. We all know what happens when a battery fails to get recharged. To prevent getting stranded, it is important to head immediately to a service location.

HINT: A faulty alternator or loose belt is usually the culprit when a vehicle’s battery is not recharging.


Piston rings maintain combustion pressure in the cylinder and prevent oil from seeping into the combustion chamber. Ring failure results in white exhaust smoke, excessive oil consumption, and compromised performance. To verify the need for piston ring maintenance, the technician uses a compression tester to check for low compression readings. The technician may also refine the check by squirting some medium-weight oil into each plug hole, cranking the engine, and repeating the compression test. If the readings are significantly higher, there is a problem with the rings or cylinder. If no changes are evident, the trouble is with the valves. A significant drop in pressure in one or more cylinders can be indicative of several problems, including a blown head gasket.

HINT: A broken compression ring may produce a misfire in the affected cylinder.


Back when most automobiles were outfitted with drum brakes, uneven braking (often referred to as “brake pull”) was quite common. But even though self-adjusting disc brakes have become more the rule than the exception, uneven braking can still be a problem. Although self-adjusting disc brakes are supposed to automatically compensate for pad wear, it’s still possible for one side of the braking system to slow the vehicle more than the other side, causing the brakes to “pull” to one side. Brake pull can be the result of a sticking caliper that is triggered by corrosion that reduces the clearance between the piston and the caliper bore. A worn or damaged piston seal may also cause a caliper piston to stick.

HINT: Old, dirty, contaminated brake fluid can rust and corrode internal brake components, which is why the fluid should be replaced according to schedule.


If your car battery is dead and someone is willing to give you a jump start, attach the red positive cable clamp to the positive (+) battery terminal of the dead battery. Then, secure the red positive cable clamp on the other side of the jumper cables to the functioning vehicle’s positive (+) battery terminal. Next, connect the black negative cable clamp to the working battery’s negative (-) battery terminal; however, don’t connect the black negative cable clamp to the dead battery. Instead, attach it to an unpainted, metal part of the car. Start the working vehicle, then wait a minute to start the dead car. Once the dead vehicle is running, disconnect the cables starting with the black clamps.

HINT: When jump starting a vehicle, do not let the clamps touch each other while any part of the cables is still attached to a car.


When drivers hear unusual or excessive noise coming from under the hoods of their vehicles, it may be indicative of an engine problem. If a clicking or tapping noise is heard that gets louder as the engine is revved, it may be an upper valve train (“tappet”) noise caused by low oil pressure, excessive valve lash, or worn or damaged parts. This should prompt a check of the dipstick to see if the engine oil is low. If it is, oil should be added. If the engine is still noisy, a worn or damaged oil pump, a clogged oil pump pickup screen, or a plugged oil filter may be preventing normal oil pressure from reaching the upper valve train components.

HINT: Using motor oil with too thick a viscosity during cold weather can also slow down the flow of oil to the upper valve train, causing noise and wear.


While oil pressure gauges are no longer included among the dashboard instrumentation of modern automobiles, we now have oil pressure warning lights. Oil pressure gauges act as indicators of the engine’s overall well-being and as early warning systems. A zero reading with the engine running above idle indicates that the gauge is faulty, the oil level is much too low, or the oil pump (or its drive) has broken. In any case, the engine should be turned off immediately. For vehicles not equipped with oil pressure gauges, the illumination of the oil pressure warning light (an icon of an oil can) should elicit the same response. Engines that continue to run without sufficient oil will run dry, overheat, and seize.

HINT: Low levels of engine oil may be caused by leaky gaskets or seals, or worn valve guides, piston rings, and/or cylinders that are causing the engine to burn oil.


If your vehicle idles roughly, is hard to start, or displays a CHECK ENGINE light, chances are there is a problem with the canister purge solenoid. This emissions component is commonly found in the “evaporative emissions control system” (EVAP), which reduces evaporative emissions pollution created by the vehicle’s fuel in the form of vapors. The EVAP system collects and recirculates these vapors so that they can be used as fuel and not escape as pollution. It is the job of the canister purge solenoid to “purge” the EVAP system by acting as a switch that allows vapor into the engine. When this purge solenoid fails, it can adversely affect the vehicle’s emissions output levels and cause the symptoms mentioned above.

HINT: If the canister purge valve solenoid fails and remains open, it will create a vacuum leak that can affect the engine idle speed and quality.


Exhaust systems are designed to provide free-flowing yet slightly restricted passage for exhaust gases to escape the combustion chamber. The design causes a phenomenon called the “venturi” effect in which the airflow is speeded up. This allows the engine to breathe responsively as the driver accelerates and decelerates, thereby optimizing engine performance. So, while slight resistance, or “backpressure,” is designed into the exhaust system, a restriction introduced into the system by a collapsed exhaust pipe, clogged catalytic converter, or plugged muffler is very unwelcome. Transmission shifting, electronic engine controls, fuel delivery, and emission systems will be negatively affected. The restriction must be corrected. Symptoms of too much backpressure include lack of high-speed power, poor fuel economy, and overheating.

HINT: A plugged catalytic converter can strangle engine breathing and cause a big drop in engine performance and fuel economy.


If you are conscientious enough to pop the hood and check your engine oil on a regular basis, try going one step further and check the master cylinder to inspect the condition of the brake fluid. If the normally clear fluid is dark, it should be drained and replaced. In fact, it is a good idea to flush the braking system every two to three years (sooner, if the owner’s manual so indicates) as a preventive measure. Because brake fluid attracts moisture, any water that gets into the system will eventually rust and damage brake parts from the inside. Flushing the system of contaminated brake fluid on a regular basis helps avoid an expensive rebuild of the system.

HINT: A good rule of thumb is to have your vehicle’s brakes flushed about every 30,000 miles.


If you are conscientious enough to pop the hood and check your engine oil on a regular basis, try going one step further and check the master cylinder to inspect the condition of the brake fluid. If the normally clear fluid is dark, it should be drained and replaced. In fact, it is a good idea to flush the braking system every two to three years (sooner, if the owner’s manual so indicates) as a preventive measure. Because brake fluid attracts moisture, any water that gets into the system will eventually rust and damage brake parts from the inside. Flushing the system of contaminated brake fluid on a regular basis helps avoid an expensive rebuild of the system.

HINT: A good rule of thumb is to have your vehicle’s brakes flushed about every 30,000 miles.


When a wheel hub bearing becomes worn, pitted, or contaminated, drivers may detect clicking, grinding, knocking, or humming noises. Drivers may also notice excessive wheel vibration, wobbling, or shimmying. Because so much weight is riding on the wheel bearings (and so much load is exerted on them in cornering maneuvers), even the smallest amount of damage on the bearings’ surfaces can cause a lot of noise. In addition, internal sensors may become unable to perform, which may lead to ABS failure. Moreover, wheel bearings do not have a constant supply of oil to lubricate and cool them, which means they have to be self-sufficient and tightly sealed. These sealed bearings must be replaced, not serviced.

HINT: Because a worn wheel hub bearing generates more heat than a good bearing, a worn bearing can sometimes be detected by lug nuts that are hotter than those on the other wheels.


Owners of older vehicles needing repairs may wonder if it’s worth it to keep the car or simply buy a new one. Sentiment aside, anyone who is faced with a repair bill that approaches what it would cost to buy another vehicle would likely purchase another one. If the repair cost is much less, many find it a good idea to keep a car with which they are generally happy. What about automobile owners facing a moderate repair bill who still want a new car? In most cases, it pays to make the repair before selling since the car will command a higher price as well as appeal to more prospective buyers if it is in good overall condition.

HINT: Vehicles that are kept free of dings, dents, chips, and rust are more appealing to buyers at the time of their eventual sale.


Vehicle manufacturers generally recommend changing the engine coolant every two years, but there is no reason to stop there. At the same time, perform a check of the hoses and clamps. The hoses leading to and from the radiator have a useful life span of approximately four years. If you can remember your last coolant flush but cannot remember the last time the hoses were changed, chances are that the upper and lower radiator hoses, at the very least, are due for replacement. When squeezing a coolant hose, if the ends of the hose feel softer than the mid-section, it is likely that the hose will fail from the inside with either a burst or a pinhole leak.

HINT: When the process of electrochemical degradation (chemical reaction that weakens the hose) produces radiator hose failure from the inside, the damage will not be visibly apparent.


A “timing belt” or “timing chain” connects the crankshaft to the camshaft(s) so that an engine’s valves open and close in proper sequence during each cylinder’s intake and exhaust strokes. Because timing belts are primarily composed of rubber and synthetic fibers, they are subject to wear and breakage that can lead to severe damage in an “interference engine,” in which the pistons would strike the valves. To avert this catastrophic possibility, auto manufacturers strongly recommend that timing belts be replaced every 40,000 to 100,000 miles. And although metal timing chains are not as susceptible to breakage, they are subject to wear, as are chain tensioners, chain guides, and silencers. All these components should be checked for wear and proper lubrication.

HINT: When a timing chain wears out, it stretches and the ignition and valve timing become more retarded, which can cause an engine to feel sluggish and low on power.


A constant velocity (CV) axle has two “CV joints” (an inner and an outer), which allow the axle to transfer the engine’s power to the drive wheels at a constant speed while accommodating for the different travel. Packed in grease and covered with rubber boots, CV joints don’t require any maintenance, but they should be regularly inspected for leaks and cracks. Deteriorating boots can begin to leak grease, which will splatter on the inside of the wheel and on the suspension. This cannot be seen from the outside of the vehicle and must be viewed from underneath. Replacing a boot immediately after a leak is found costs far less than what it would cost to replace a CV joint.

HINT: The outer CV joint almost always fails before the inside one does because it does more work than the inner joint.


If you are concerned that you are spending too much money on gasoline to run your vehicle, you might want to check that you are using the appropriate fuel. It is estimated that American drivers wasted more than $2.1 billion during the most recent years for which data was available by using premium-grade fuel in vehicles that are designed to run on regular gas. According to a recent comprehensive fuel evaluation by AAA, 16.5 million U.S. drivers chose to use premium fuel in the last year, despite vehicle manufacturers’ recommendation to use regular-grade fuel. These drivers should be made to understand that premium-grade gasoline has higher octane (93) than regular fuel (87), but not better quality.

HINT: The “octane rating” of gasoline indicates how much the fuel can be compressed before it spontaneously ignites. It is a measure of a fuel’s ability to resist “knock.”


If your engine is losing power, misfiring, or idling roughly, it may have a “burned valve.” This can be diagnosed with a compression test, which measures the pressure in all cylinders. A pressure gauge that shows lower than normal pressure indicates that pressure is leaking out of the combustion chamber. A burned valve cannot hold a seal due to concentrated heat and pressure that eat away (burn) the edge of the valve. To repair a burned valve, it is necessary to remove the cylinder head, replace the bad valve, and reface/repair the valve seat. If one valve has failed, preventive maintenance and common sense usually dictate that all valves be replaced at the same time.

HINT: Replacing a burned valve will not fix a compression problem if the underlying cause is a hot spot in the cylinder head.


When a brake pedal has a spongy feel, it can be due to a defective master cylinder or a twisted brake line. Usually, however, the cause can be traced to air in the hydraulic system, as the elasticity of the air creates the mushy feel of the brake pedal. To remove the air, the system must be “bled.” Air usually enters the system via a leak in the brake system’s hydraulic lines, or when the brake fluid level drops below the minimum point. The usual culprits are a flexible fluid line that breaks, worn seals in the master cylinder, or a braking caliper that allows air to seep past. After repairing the leak, new brake fluid must be installed.

HINT: Because brake fluid absorbs moisture over time, causing brakes to be less responsive, it should be flushed and changed according to the manufacturer’s recommendations, usually every two years.


When a vehicle’s exhaust system allows combustion byproducts to escape before they have safely passed to the rear of the automobile, driver and passengers may be exposed to potentially lethal exhaust fumes. A leaky exhaust system is also very noisy and can adversely affect performance by eliminating the back pressure needed for a vehicle to drive. With this in mind, it is best to get ahead of the game by having the exhaust system inspected every time the vehicle goes up on the lift. At the first sign of corrosion, rust, or road damage, have the necessary repairs and/or replacements made by an experienced technician. A damaged exhaust system is not a candidate for patches or inexperienced hands.

HINT: An exhaust leak near the manifold can decrease a vehicle’s fuel efficiency by as many as 3 to 4 mpg because the sensors that read incoming and outgoing oxygen are thrown off by the leak and compensate by burning excessive amounts of fuel.


Thick, white smoke coming from the exhaust pipe indicates a problem. Billowing smoke of this type warrants immediate attention since it is likely due to the engine burning coolant, which can be the result of a blown head gasket, a damaged cylinder head, or a cracked engine block. It should be noted that even a small coolant leak can lower the engine’s coolant level to the point where overheating and serious engine damage may occur. A coolant leak into the engine’s oil system may not produce exhaust smoke, but could cause the oil to become thin and milky-looking and the coolant to look like brownish sludge. This type of coolant leak also requires a professional check.

HINT: It is normal for wisps of water vapor to emerge from a tailpipe upon starting the engine.


When piston rings become so worn that they allow hot engine gases to escape into the crankcase, the resultant “blow by” causes a decrease in horsepower due to loss of some of the high pressure pushing the piston. In addition, contaminates from incomplete combustion may migrate into the crankcase oil, which will lead to dilution. If blow by is allowed to continue and worsen, it can allow engine oil to leak by the rings into the combustion chamber, where it can reduce the octane rating of the mixture. The consequent “detonation” (premature spontaneous burning of a fuel–air mixture) can cause severe destruction of the piston and chamber. For these reasons and others, worn piston rings should be replaced.

HINT: Wear of piston rings, the circular components fitted into grooves in the pistons, can be confirmed by a compression test.


When an ear-splitting squeal comes from beneath the hood during a morning start-up, chances are the “serpentine belt” is the culprit. Serpentine belts replaced old-fashioned V-belts during the 1970s, when power-hungry accessories made it necessary to have as many as four belts running off the crankshaft pulley. In their place, a single serpentine belt winds through numerous pulleys to power every engine accessory. Most serpentine belts utilize a spring-loaded tensioner pulley that exerts a constant preload on the belt, which eliminates the need to adjust the tension. Serpentine belts can last as long as 150,000 miles with no maintenance. A squeal from the belt may be due to a worn belt, misaligned pulleys, or a seized tensioner or idler pulley.

HINT: Cracks across the ribs are the most common indication of a serpentine belt that is approaching the end of its life span.


When engine mounts become worn, damaged, or broken, they can cause clunking, banging, and other impact-type sounds that result from the weight of the engine shifting excessively to the point of contact. Marks on the radiator indicate that this might be the problem. In vehicles in which the engine faces forward with the cooling fan being driven by a belt, these marks are a likely indication that worn mounts are allowing the engine to lurch forward in the engine compartment. Unlike older engine mounts, which were composed of simple slabs of rubber, today’s mounts are precisely engineered into specific shapes, with some filled with silicone or hydraulic fluid. It is important to replace worn and damaged mounts with like components.

HINT: Besides indirectly breaking engine parts, bad engine mounts can lead to damaged belts and hoses.


“Control arms” attach the suspension to the chassis and manage the motion of the wheels in accordance with the vehicle’s body. Each of the several control arms (upper and lower) utilize bushings at points of attachment, which absorb all of the vehicle’s front-end loading during braking, cornering, and steady highway driving. When these bushings wear, drivers may experience steering-wheel vibration and clunking noises coming from the front suspension. At this point, it is recommended that the vehicle undergo a good drive test, during which the auto technician can feel and hear the automobile respond to left and right cornering, hitting bumps, and braking and accelerating. Afterward, placing the car on a lift can confirm any need for control-arm replacement.

HINT: In some cases, worn out control arm bushings can be replaced separately.


Because it is the fuel pump’s job to see that gasoline gets from the tank to the engine, the failure of this component will bring a vehicle to a stop. One of the earliest indicators of an old or worn fuel pump is a loud whining sound or howl when the engine is running. Other indicators of impending fuel-pump failure are faulty engine performance, including hard starting; misfires; a loss in power and acceleration; a decrease in fuel efficiency; and even engine stalling. If the fuel pump fails completely, the engine will not start at all due to lack of fuel. Because many other issues can lead to a no-start condition, it is important to have the problem properly diagnosed.

HINT: A possible cause of fuel-pump failure is regularly having less than a quarter tank of fuel.


As turbocharging becomes an ever more popular means of increasing performance and mileage, owners of turbocharged vehicles should better familiarize themselves with the symptoms of damage. To begin with, in vehicles equipped with a boost gauge, if the gauge is not going up as much as it previously did, there is a good chance that the turbo is in need of repair. Symptoms also may include power loss, blue/gray exhaust smoke, and a loud whining noise. These may be indications of a cracked turbo housing or blown internal seals that allow oil to leak into the exhaust system, or a damaged or abraded compressor wheel and/or turbine blades. These and other symptoms should prompt a comprehensive turbocharger analysis.

HINT: Because a turbocharger is driven by expanding exhaust gases (unlike a supercharger that is driven by engine power), it is said to be a free source of power.


The alternator plays a critical role in charging the car battery while supplying other systems with the power they need to run properly. To do so, this belt-driven component produces alternating current (AC), which is converted to 12-volt direct current (DC). As the alternator cycles on and off in response to the electrical demands placed upon it, the battery acts as a buffer. At peak efficiency, the alternator should be charging no more than about half the time in order to preserve its life expectancy. However, the reality of alternator life is that such electrical systems as car stereos, daytime running lights, seat heaters, etc., place such demand on alternators that they may only provide 3-4 years of service.

HINT: Signs that an alternator may be failing are dim lights, a warning light on the dashboard, and a “whining” noise before the alternator gives out.


If your vehicle has an automatic transmission, it makes good sense to have the automatic transmission fluid in your vehicle changed about every three years or 60,000 miles, more frequently if you tow or carry heavy loads. Inspection of the fluid may show some sediment in the transmission pan due to organic friction material from the clutches and bands, which is normal. A certain amount of metal flaking from metal-to-metal wear is also acceptable. However, metal flakes from spalling bearings and chips from gear teeth should raise concerns. An experienced auto technician will be able to get a lot of information from the content, color, and smell of drained automatic transmission fluid.

HINT: If contaminates are allowed to remain in transmission fluid, they will shorten the life of the transmission.


If your vehicle’s engine is difficult to start, stalls after starting, hiccups, or hesitates under acceleration or while idling, it is likely that a faulty “mass airflow sensor” (MAS) is the reason. This sensor measures the mass of air entering a vehicle’s fuel injection engine and then transmits the data to the Engine Control Unit (ECU) so that it can balance and deliver the correct amount of fuel to the engine. To avoid problems, it is generally recommended that the MAS be cleaned every few months or at the time of an oil change. This involves removing the sensor and cleaning it with a special cleaner, drying the sensor, and reinstalling it without damaging the delicate wiring.

HINT: A faulty mass airflow sensor will trigger the CHECK ENGINE light on the dashboard.


The ignition coil’s job is to transform the low-voltage power from the battery into the thousands of volts required to produce the electric spark in the plugs to ignite the fuel. If the gap in the spark plugs widens due to normal erosion, additional voltage may be required to create a spark in the chamber. As a result of these increased voltage demands, more current flows through the primary circuit, which can overload the primary resistor. These conditions may lead to ignition coil failure by forcing the ignition coils to operate at a much higher output. Symptoms include backfiring, engine misfiring, stalling, and reduced fuel economy. Replacing spark plugs regularly can help avert the need to replace an ignition coil.

HINT: Backfiring, which occurs when unused fuel is emitted through the exhaust system, can lead to exhaust-system damage.


If it takes more effort to steer your vehicle than you previously noted, the loss of power assist may be due to lack of steering fluid pressure. Locate the reservoir to check the level of the steering fluid. If the level is low, it is important to find out where the fluid is leaking. Because many newer vehicles have undercarriage pans that catch leaking fluid before it hits the garage floor, it may be necessary to enlist the help of an experienced auto technician to find the leak. If the loss of power assist is not caused by leaking fluid, it is necessary to put the vehicle on a lift to look for binding components.

HINT: If the wheels can be moved from one end of the steering range to the other smoothly when the vehicle is on a lift, the problem is likely to be in the steering assist system rather than physically binding components.


Even on the coldest of days, the temperature of the air pouring from your vehicle’s cabin heater should reach at least 120 to 130 degrees F. If not, it may be due to an accumulation of rust and sediment in the heater core that has reduced its efficiency. Before thinking of replacing it, try having the cooling system flushed. At the same time, the engine thermostat should be replaced. Aside from clogging the heater core and compromising its ability to heat the car’s interior, failure to drain and flush the car’s cooling system regularly (every three years) also causes antifreeze to lose its rust-inhibiting properties and ability to prevent corrosion. This can lead to a clogged radiator.

HINT: If the heat in your vehicle is not working, a worn-out thermostat might be preventing the coolant from getting warm enough to heat the cabin.


Some car owners may wrongly conclude that since a 50/50 mixture of antifreeze and water works so well in their cars’ cooling systems, increasing the antifreeze level will provide even more protection. However, under normal circumstances, a 50/50 mixture does the job intended by providing freezing protection down to minus 34 degrees Fahrenheit and boiling protection up to 275 degrees. Following the “more is better” dictum by increasing the percentage of antifreeze may extend these limits a little, but the extra cost is hardly worth the very moderate increase. Consider that pure antifreeze is not an optimal heat conductor. Thus, if a coolant is to be effective, it must incorporate the heat-conducting qualities that water brings to the mix.

HINT: Because antifreeze’s additives gradually lose their protective qualities, a vehicle’s coolant should be checked regularly.


The ultimate assessment of any vehicle that you are thinking of purchasing is a test drive. Begin by noticing the ease with which you enter the vehicle; the comfort, position, and adjustment of the seat and steering wheel; and the position of the various controls and mirrors. Take a route that includes everything from stoplights to sharp turns to highway driving in order to get a feel for the vehicle’s acceleration, braking, and handling in a variety of conditions. Go over bumps and evaluate the suspension. After you have tested the radio, turn it off and listen for creaks and rattles. Listen to wind noise at highway speeds while checking that the vehicle tracks straight.

HINT: Car buyers should test drive a vehicle before negotiating price.


The “head gasket” is positioned between the engine block and cylinder heads, where its job is to seal the cylinders; preserve engine compression; and prevent oil, fuel, or coolant leaks. When a gasket ruptures, symptoms include coolant mixing into the engine oil, oil leaking from the engine, or an engine misfire, depending on where the break in the head gasket occurs. If the oil mixes with the coolant, their cooling and lubricating properties can be compromised to the point where the engine will fail. An early sign of this problem is contamination that looks like milk chocolate on the oil dipstick. These and other signs should prompt an immediate check by an auto technician.

HINT: While the head gasket is a relatively inexpensive part, the labor involved to replace it can be costly.


One of the most important components of a vehicle’s emissions control system is the “catalytic converter,” which converts harmful exhaust gases (such as carbon monoxide) into relatively innocuous gases (such as carbon dioxide, nitrogen, and oxygen) and water. To perform its exhaust-cleaning function, the catalytic converter is placed between the engine and the tailpipe. As the exhaust gases pass through the converter (honeycomb plates plated with platinum and other very expensive metal), chemical reactions take place that convert potentially poisonous gases into safer gases. If a CHECK ENGINE LIGHT comes on, the vehicle’s fuel efficiency suddenly drops, the vehicle does not start or accelerate, or the vehicle fails an emissions test, the catalytic converter may need to be replaced.

HINT: A bad oxygen sensor, a coolant leak, and using oil with improper viscosity can lead to catalytic converter overheating and failure.


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