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 Is there any way I can tell if my air conditioner needs refrigerant?
There are several ways to determine if your air conditioner is low on refrigerant.
Poor cooling. If your air conditioner isn't putting out much cold air, it could be low on refrigerant. But an A/C system can still produce cool air even if it has lost up to 50% of its original charge of refrigerant. Even so, output will be reduced. If the system is working properly, it should blow air that is approximately 50 degrees cooler than the ambient air temperature.
Poor cooling, however, doesn't necessarily mean the refrigerant is low. You might have another kind of problem. So to determine the cause, the system should be diagnosed by a skilled professional who understands air conditioning.
If your A/C system has a "sight glass" (a small round glass window usually located on or near the receiver/drier or accumulator), you can "see" inside the system. Refrigerant is clear so it's hard to tell if the system is full or empty.
If the glass looks clear and there is no cold air output, the system has lost its charge of refrigerant through a leak somewhere in the system. If you see bubbles or foam in the sight glass, it means the system is low on refrigerant and needs to be recharged.
The most accurate means of determining the refrigerant level in your A/C system is with a set of A/C gauges. The gauges will show how much pressure is in the high and low sides of the system. The pressure specs vary from application to application, but generally speaking a high side reading of less than 160 lbs. at 80 degrees F, and/or a low side reading of less than 16 to 22 lbs. at 80 degrees F indicates a need for additional refrigerant.
If you see oily streaks radiating outward around the compressor shaft seal, or wet oily areas around hose connections, it means refrigerant is leaking from your system. This too, may indicate a need for additional refrigerant to replace that which has been lost.
Most A/C systems leak a little refrigerant over time. Newer systems are tighter and leak less than older ones, which may lose up to several ounces of refrigerant a year. After five or six years of service, therefore, it's not unusual for the system to need some additional refrigerant.
If your A/C system can't hold a charge from one season until the next, it has a major leak that should be pinpointed and repaired. The type of refrigerant (R12) used in all vehicles built prior to 1993 causes damage to the Earth's protective ozone layer. So leaks should be repaired to prevent the loss of refrigerant.
Is it better to use a "wax" or a "sealer" to protect my car's finish?
Both types of products will protect your paint against moisture, ozone and ultraviolet. Sealers, which are typically petroleum based and contain silicones, usually last much longer (up to a year or more) than ordinary wax. But the distinction between these two products is blurring because many waxes now contain silicone and other ingredients designed to extend protection.
A wax or sealer that is applied by rubbing it on your car's finish will always give you better protection than a product that's sprayed on at a car wash. Car wash waxes give a nice temporary shine, but don't provide lasting protection.
When choosing a wax or sealer, choose one that's "right" for your vehicle's finish. Most newer cars and trucks have what's called a "base coat, clear coat" finish. Over the base color coat of paint is a layer of clear paint to provide added shine and protection. Some car makes say it isn't really necessary to wax or seal a base coat, clear coat paint job. But it certainly isn't going to hurt anything -- provided you use a product that is designed for this type of finish.
CAUTION: Wax or sealer for a base coat, clear coat finish should contain no abrasives or polish. Abrasives are often added to wax to remove the oxidized layer from the surface of the paint. When the wax is applied, it has a polishing effect that helps shines up dull, faded paint. It works great on solid color finishes, but not clear coated finishes because it scratches and dulls the clear coat.
APPLYING WAX & SEALER
Always follow the instructions that come with the product.
Wash and dry your vehicle before you wax it.
Don't wax it in the direct sun during the heat of the day. Wax in in the shade, or early in the morning or late in the day when the sun isn't so hot.
Use a clean, soft, damp rag or sponge to apply the wax or sealer.
Avoid getting wax or sealer on the glass or on matte black finished moldings or paint, or on a vinyl roof.
Apply wax to a small area (a door, fender, half the hood, etc.), then let it dry before wiping and buffing. Then move on to the next area and repeat until the job is done. If you try to do the whole car or too large an area, the wax or sealer may have too much drying time and be difficult to wipe or buff off.
Elbow grease works best. Power buffers are faster, but require skill to do a really nice job. CAUTION: If using a wax or polish that contains an abrasive, excessive force on a power buffer may buff right through the finish!
You shouldn't have to repeat the job until water no longer beads up on the finish when your vehicle is wet.
How do I know when my car really needs a brake job?
You need a "brake job", when your brake linings are worn down to the minimum acceptable thickness specified by the vehicle manufacturer or the applicable state agency in areas that set their own requirements. The only way to determine if new linings are required, therefore, is to inspect the brakes.
You may also need a brake job, if you're having brake problems such as grabbing, pulling, low or soft pedal, pedal vibration, noise, etc., or if some component in your brake system has failed. But if the problem is isolated to only one component, there's no need to replace other parts that are still in perfectly good working order.
There is no specific mileage interval at which the brakes need to be relined because brake wear varies depending on how the vehicle is driven, the braking habits of the driver, the weight of the vehicle, the design of the brake system and a dozen other variables. A set of brake linings that last 70,000 miles or more on a car driven mostly on the highway may last only 30,000 or 40,000 miles on the same vehicle that is driven mostly in stop-and-go city traffic.
As a rule, the front brakes wear out before the ones on the rear because the front brakes handle a higher percentage of the braking load -- especially in front-wheel drive cars and minivans. So many service facilities advertise $59.95 brake job "specials" that replace the linings on the front brakes only. Doing the front brakes only is okay and can save you money, as long as, the rear brakes are in good condition. But if the rear brakes need attention, they should be relined too.
One of the problems with the brake specials you see advertised in the newspaper is that the price is very misleading. A person typically goes in expecting to spend $59.95 for a brake job, but usually ends up spending considerably more because the brakes need more than the minimum amount of work to restore them to like-new condition. The price of a brake job depends entirely on the work that needs to be performed. So any advertised special is not a firm price, but only an estimate of the least amount of money it might cost you to get your brakes fixed. A price should not be quoted until after the brakes have been inspected. Then and only then can an accurate determination be made of the parts that actually need to be replaced.
My mechanic says I have a bad voltage regulator, and he has to replace my alternator. How come?
The voltage regulator controls or regulates the alternator's output. Think of it as the brains of the charging system. It senses how much voltage is needed by your vehicle, then modifies the field current within the alternator so it puts out just the right amount of current. Too little current can allow the battery to run down while too much can damage it and other electrical and electronic components. When the regulator fails, the charging system usually ceases to function -- except in cases where the nature of the failure causes the alternator to run wild and overcharge the battery. In any event, the only cure for a dead or defective regulator is replacement.
In older vehicles, the regulator was a separate component usually mounted somewhere in the engine compartment. If this type of regulator failed, it could be easily replaced in a matter of minutes with a new one. But for the last decade or more, most regulators have been mounted in or on the alternator itself. This was done by the vehicle manufacturers to simplify wiring and assembly. It was also made possible by advances in electronics that allowed the regulator to be reduced in size to a small chip.
Charging systems that have a separate regulator mounted away from the alternator are referred to as "externally regulated" charging systems while those that have the regulator in or on the alternator are called "internally regulated" charging systems. On some vehicles there is no regulator at all! Voltage regulation is controlled by the engine computer.
Unfortunately, internally regulated alternators are packaged as a unit -- which means that if either component fails (alternator or regulator) both must be replaced. This is because internal regulators are not available separately (at least not to the general public or the typical service facility). Electrical shops and remanufacturers who rebuild alternators can get them and can replace the regulator separately if that's all that's wrong with the unit -- but they'll usually charge you the same as if you bought a rebuilt alternator.
The truth is, the high cost of labor today has made it impractical for most service facilities to fool around trying to rebuild or repair components like alternators, starters, carburetors, front-wheel driveshafts, transmissions and even engines. It's faster, easier and usually cheaper to simply replace the old unit with a new or remanufactured one than to try to overhaul or fix it. Besides, most new and remanufactured parts come with a guarantee.
How can I tell if my battery is good or bad?
The condition of the cell plates inside the battery determines whether or not a battery is still serviceable. Current is produced when sulfuric acid in the battery reacts with lead in the cell plates. As the battery discharges, sulfate accumulates on the plates and reduces the battery's ability to make current. The sulfate is returned to solution when the alternator recharges the battery by forcing current to flow in the opposite direction.
Over time, some of the sulfate becomes permanently attached to the plates. The sulfate forms a barrier that diminishes the battery's ability to produce and store electricity. This process can be accelerated, if the battery is run down frequently or is allowed to remain in a discharged state for more than a few days. If the plates have become sulfated, therefore, the battery won't accept a charge and will have to be replaced.
Average battery life is only about four to five years under the best of circumstances -- and sometimes as short as two to three years in extremely hot climates such as Arizona and New Mexico. But the battery may become "sulfated" prematurely, if it is chronically undercharged (charging problems or frequent short-trip driving), or if the water level inside the battery drops below the top of the cell plates as a result of hot weather or overcharging and allows the cell plates to dry out.
BATTERY TESTING
This is something you can't really do yourself, so you need to take your vehicle to a service facility that has the proper test equipment. The battery's condition can be determined one of two ways: with a carbon pile "load test" (that applies a calibrated load to the battery) or electronically with a special tester that measures the battery's internal resistance.
Equipment that uses a carbon pile for load testing requires the battery to be at least 75% charged. If the battery is less than 75% charged, a good battery may fail the test. So the state of charge must be checked first, and the battery recharged, if it is low prior to testing. NOTE: The battery does NOT have to be fully charged prior to testing, if an electronic tester that measures internal resistance is being used.
If load testing with a carbon pile, apply a load that is equal to half the battery's cold cranking amps (CCA) rating. A good battery should be able to supply half its CCA rating for fifteen seconds without dropping below 9.5 volts.
My power steering feels stiff when I first start my car, but then feels normal after I've driven the car awhile. How come?
This is called "morning sickness" and has nothing to do with being pregnant. The condition is caused by wear in the spool valve housing on certain power steering racks -- notably GM front-wheel drive cars.
When the car is first started, the rack is cold and clearances in the spool valve are at their greatest. Hydraulic pressure from the power steering pump leaks past grooves worn in the aluminum spool valve housing. This causes a loss of pressure and increases steering effort. The steering feels stiff with little or no power assist. As the car is driven, the rack warms up. This decreases the clearances inside the spool valve housing, which reduces the leakage past the grooves. More pressure goes to where it is supposed to go and the steering becomes easier as power assist returns.
The "fix" for this condition is to replace the rack with a new one (preferably with a cast iron spool valve housing) or a remanufactured rack that has a stainless steel sleeve pressed into the aluminum housing.
When I try to start my engine, nothing happens. It won't even crank. All I hear is dead silence. What's wrong?
Assuming you're not deaf, you have a starting problem that may be due to a dead battery, a loose or corroded battery cable, a bad ignition switch, an open neutral safety switch, or a bad solenoid or starter.
Total silence usually means no juice is getting through to the starter. So start with the battery. Is is dead or does it still have a full charge? Are the battery cables loose, corroded or damaged? Be sure to check both ends of the cables, including the starter and ground connections.
If you don't find any obvious problems with the battery or its connections, voltage may not be passing through the ignition switch circuit to the starter solenoid. A voltmeter or 12 volt test light can help you see if voltage is reaching the solenoid when you turn the key.
If voltage isn't getting through, try jiggling the gear shift lever. Some vehicles may also have a safety switch on the clutch pedal that prevents the engine from starting unless the clutch pedal is depressed. Use your voltmeter or test light to isolate the component that needs to be replaced or adjusted. Sometimes the transmission or clutch linkage may need to be adjusted for the safety switch to work properly.
If voltage is getting through the ignition switch circuit, but the starter isn't doing anything, check the wiring connections on the solenoid and starter. Are they clean and tight? Try bypassing the solenoid. Refer to a shop manual for the proper terminals, then jump the one that routes voltage directly to the starter (usually B+ or BAT). If the starter spins, the problem is a bad solenoid (or poorly grounded solenoid). If nothing happens, the problem is a bad starter that needs to be replaced.
My brake warning light is on. What does it mean?
If the light is on all the time, it could mean you simply forgot to release the parking (emergency) brake. The brake warning light remains on when the brake is set as a reminder. If the brake warning light remains on when the parking brake is released, then something is amiss.
In some cases, the brake warning light may remain on if the switch on the parking brake pedal or lever is misadjusted. Nothing is wrong with the brakes and a simple adjustment should fix the problem.
If the brake warning light comes on when you apply the brakes, or is on continuously, it means that hydraulic pressure has been lost in one side of the brake system or that the fluid level in the master cylinder is dangerously low (due to a leak somewhere in the brake system). In either case, the fluid level in the master cylinder should be checked. Adding brake fluid to the master cylinder reservoir may temporarily solve the problem. But if there's a leak, the new fluid will soon be lost and the warning light will come back on.
Brake fluid leaks are serious because they may cause the brakes to fail! So avoid driving the vehicle until the system can be inspected to determine what's wrong. Leaks can occur in brake hoses, brake lines, disc brake calipers, drum brake wheel cylinders or the master cylinder itself. Wet spots at hose or line connections would indicate a leak that needs to be fixed.
Leaking brake fluid can also contaminate the brake linings, causing them to slip or grab. The uneven braking action that results may cause the vehicle to veer to one side when the brakes are applied. Brake shoes or pads that have been contaminated with brake fluid cannot be dried out and must be replaced.
BRAKE WARNING LIGHT CIRCUIT
The brake system is divided into two hydraulic circuits. On most rear-wheel drive vehicles, it is divided so one circuit applies the front brakes and the other applies the rear brakes. On front-wheel drive cars and minivans, the system is usually split diagonally. One circuit works the right front and left rear brake, and the other works the left front and right rear brake. This is done for safety purposes so if one circuit loses all its brake fluid and fails, the vehicle will still have one remaining circuit to apply two wheel brakes.
Usually located on the master cylinder or the brake lines exiting the master cylinder is a "pressure differential" switch. If either brake circuit develops a leak and loses its fluid, the difference in pressure when the brakes are applied will trip the differential switch causing the brake warning light to come on.
ABS WARNING LIGHT
On vehicles equipped with antilock brakes (ABS), a second warning light is provided to warn if a problem occurs within the ABS system. The ABS lamp comes on when the ignition is turned on for a bulb check, then goes out after the engine starts. If the ABS warning light remains on or comes on while driving, it indicates a fault has occurred in the ABS system.
What happens next depends on the nature of the fault. On most applications, the ABS system disables itself if the ABS warning light comes on and remains on. This should have no effect on normal braking. Even so, ABS will NOT be available in an emergency situation or when braking on a wet or slick surface.
CAUTION: If the brake warning light also comes on and remains on while the ABS warning light it on, it signals a serious problem. Your vehicle may not be safe to drive. The brakes and ABS system should be inspected immediately to determine the nature of the problem!
If the ABS light comes on momentarily then goes out, the nature of the problem is usually minor and the ABS system usually remains fully operational. Some vehicle manufacturers call this kind of fault a "nonlatching" fault (meaning it isn't serious enough to disable the ABS system).
Regardless of the type of fault that occurred to trigger the ABS warning lamp, a special "code" is recorded in the ABS module's memory to aid in diagnosing the problem. On some vehicles this code can be retrieved by putting the ABS system into a special diagnostic mode. The code is then flashed out through the ABS warning lamp. The code number refers to a diagnostic chart in a service manual that must be followed to pinpoint the faulty component. On other applications, a special "scan tool" must be plugged into the vehicle's diagnostic connector to read out the fault code.
Diagnosing ABS problems requires a fair amount of knowledge and expertise (as well as special equipment in many applications), so this job is best left to a competent professional.
My temperature warning light is on. Is it okay to drive the car?
Not unless you want to risk damaging your engine. When the temperature light comes on, it means your engine is overheating. An engine should not overheat if the cooling system is properly filled and is working normally -- even during hot weather or stop-and-go driving. Sometimes abnormal driving conditions such as towing a heavy trailer during hot weather may overload the cooling system's capacity to control heat, but usually a temperature warning light means trouble.
WHAT TO DO:
Stop driving immediately, pull over to the side of the road, shut the engine off and wait for things to cool down.
WARNING: Do not attempt to open the radiator! The radiator contains hot water under high pressure. Opening the cap could allow steam and water to blow out and burn you. There's nothing to be accomplished by opening the cap while the engine is still hot, so let your vehicle sit and cool off.
After things have cooled down (wait at least half an hour or more), then you can open the radiator cap and check the coolant level if you think it might be low. Place a rag over the cap first, and slowly turn the cap until it stops at the first detent. This should allow residual pressure to be released. Wait until all pressure has been released before removing the cap the rest of the way.
Add water to the radiator if it is low. Actually, you should add a 50/50 mixture of antifreeze and water to maintain the proper freezing, boilover and corrosion protection. But in most cases when this happens, it's an emergency situation and you don't have a jug of antifreeze handy. If that's the case, you'll have to add antifreeze later.
Visually inspect the system for leaks. Common leak points include radiator and heater hoses, the water pump and the radiator. Internal leaks (such as a crack in the head or engine) can't be seen and can only be diagnosed by pressure testing the cooling system.
IF YOU DON'T STOP DRIVING...
If you keep driving an engine that is overheating, it can cause serious damage. The engine may start to knock (caused by detonation), which in turn can cause piston, ring and head gasket damage. As the internal parts of the engine expand from the excessive heat, clearances may be reduced to the point where metal-to-metal contact occurs. Valve stems may gall and stick, and the pistons and camshaft might scuff or seize.
Severe overheating also creates tremendous thermal stress in the head(s) and block. This, in turn, may lead to cracking and/or warpage. This is a common problem with overhead cam engines that have aluminum heads.
The only vehicle that can be "safely" driven when the temperature warning light is on a late model Cadillac with a Northstar V8 engine. Cadillac engineers designed the engine control system to automatically deactivate half of the engine's cylinders if it senses an overheating problem. This reduces the heat (and power) being generated by the engine, and it allows the "dead" cylinders to pump air through the engine for internal cooling. The system is designed to provide a "limp-in" mode so the vehicle can be driven to the nearest service facility or Cadillac dealer for repairs. It is not designed for continuous driving.
My alternator warning light is on. Can I keep driving anyway?
Yes, but probably not for very long. If the alternator warning light is on, it means your charging system is not producing enough current to meet the electrical needs of your vehicle and to keep the battery charged. That, in turn, means your vehicle is running on borrowed time off the battery alone. You can keep on driving as long as the battery has enough juice left in it to keep the ignition system, fuel injectors, fuel pump and other electrical accessories working. But sooner or later, the battery will run down and your engine will die. How long this might take is anyone's guess. If you're driving during the daytime and aren't listening to the radio or running the air conditioner, the battery along might keep you going for four, five, six or more hours. On the other hand, if its nighttime and you have the lights on, the heater or air conditioner and radio, you might run the battery dead in an hour or two.
A warning light should not be ignored. It usually means something has failed and needs to be fixed -- the sooner the better in this case.
Sometimes the alternator warning light will come on, (or the amp or voltage gauge will show discharge) when nothing is really wrong with the charging system. It's a gauge or light problem. One way to tell is to turn on the headlights. If the headlights shine with normal intensity and do not change as you rev the engine, all's well with the charging system and the problem is in the warning light or gauge circuit. But if the lights are dim or get brighter as you rev the engine, you have a charging system problem that requires further diagnosis.
Any of a number of problems can cause the alternator warning lamp to come on. If the alternator drive belt is slipping, has broken or flipped itself off the pulley, the alternator will cease to produce current and the warning light will come on. If the regulator that controls the alternator's output has failed, the warning light will come on. And if there's a wiring problem in the charging circuit, the light will come on.
My oil pressure warning light is on. What should I do?
Don't ignore it. An oil pressure warning light (or low gauge reading) means one of two things: either your engine has dangerously low oil pressure (for a variety of reasons which we'll get to in a minute), or the oil pressure sending unit that triggers the warning light (or operates your gauge) has failed.
The question here is whether you have a serious problem or a minor one.
First, do not keep driving if the oil warning light is on or your oil pressure gauge has dropped. Stop the engine, let it sit for a few minutes, then check the oil level.
Is the level low? If the oil level is down more than two quarts or no oil is showing on the dipstick, adding oil to bring the level back up to the full mark may be all that's necessary to make the light go out. Just keep your fingers crossed that you haven't damaged the engine from running it too low on oil. If you hear rapping or knocking noises the engine starts, you're too late. The damage is done and now you're stuck with the consequences.
Note: On some late model vehicles, the warning light will come on (or a message will appear) if a sensor in the oil pan detects a low oil level. The light is supposed to come on before the level gets low enough to cause any damage.
If your oil level was low, it means your engine is either leaking oil or burning it. Leaks can be fixed by finding and replacing leaky gaskets and seals. Sometimes the oil filter will leak if it isn't installed or tightened properly. But an oil burning problem means the valve guides, rings and/or cylinders are worn or damaged and more costly repairs are needed.
If the dipstick shows a full oil level, then low oil obviously isn't your problem. The oil pressure may be low because of a worn or broken oil pump, a plugged oil pickup screen in the engine's crankcase, possibly a plugged oil filter or excessive bearing wear. Or, the oil pressure may be fine but the oil pressure sending unit has failed. Further diagnosis will be required to determine what's wrong.
Should you attempt to drive your vehicle home or to a service facility?
It's risky. If the problem came on suddenly, your engine does not have a lot of miles on it (less than 60,000) and you noticed no unusual noises (no valvetrain clattering or engine knocking), there's a good chance that all that's wrong is the sending unit. But, there's no way to know for sure without actually checking the engine's oil pressure with a gauge, or replacing the sending unit to see if a new unit makes the light go out. If the problem is only the sending unit, your engine still has oil pressure and you can continue to drive it until the sending unit can be replaced. But, if you're wrong you risk ruining your engine.
If you think you might have a low oil pressure or oil delivery problem because of a bad oil pump or one of the other problems we mentioned, do not drive your vehicle. Doing so only increases the probability of further engine damage. Have the vehicle towed to a service facility for repairs.
My "Check Engine" light is on. What does it mean?
It means your vehicle's onboard computer system has self-diagnosed some kind of problem. The "Check Engine" light, which is also called a "Malfunction Indicator Lamp" (MIL) or "Service Engine Soon" (SES) lamp, is there to signal you when a problem occurs that may require attention. This can include anything from a momentary hiccup that has has little or no noticeable affect on engine performance or driving safety to a failure of a major electronic component. There's no way to know what the light means without running a diagnostic scan on the system to determine the nature of the fault.
As a rule, a continuous Check Engine light usually signals a "hard fault" or failure that has occurred. If the light comes on and off, or only blinks momentarily, the problem may be minor or intermittent in nature.
To help identify the problem, it helps to make a mental note of the conditions that occurred when the light came on. Where you driving at a certain speed? Accelerating or slowing down? Shifting gears?
Onboard diagnostic systems are very complex and require a fair amount of expertise as well as special tools to troubleshoot. To find out what's wrong, a technician has to "get into" your system through a diagnostic connector which may be located under the dash, under the driver's seat or in the engine compartment. The diagnostic connector serves as a port of entry for accessing information and/or for putting your vehicle's computer system into a special diagnostic mode for further testing or displaying "fault codes".
Fault codes are numeric codes that are generated when a problem is detected. If a sensor circuit reads out of range or some electronic component fails to respond to a command from the computer, the computer recognizes it as a fault and records a number that corresponds to the nature of the problem. The technician must then retrieve the code and refer to specific diagnostic chart or "fault tree" that gives him the step-by-step checks he has to perform to isolate the failed component. It can be a very time-consuming process depending on the nature of the problem. Usually the process works but sometimes it doesn't. An intermittent fault can be very difficult to track down, and may require repeated attempts to repair it.
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