Listen to what your car is telling you

From MSN Auto
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Car Noise
Those clunks, clanks, squeaks, and rattles say a lot about a vehicle's health.

by Peter D. duPre

While most of us have seen talking cars in movies and cartoons, few of us really believe that cars can talk. OK, there have been a few production cars that told us the "door is ajar" and "the lights are on," but as a general rule cars don't speak. They do, however, have their own "language"órattles, clunks, squeaks, and mechanical noises. When your car starts "speaking," you need to listen.

We all know the everyday noises our vehicles make and become to used them. You know when your vehicle is running well because you can hear it. However, a new noise may be a warning of mechanical problems. Try to figure out where the sound is coming from and when it happens. Then, ascertain what type of sound it is, such as clicking, clanking or squealing. Your mechanic needs this information and it must be accurate. What you call buzzing, the mechanic may call a rattle.

To assure that you and your mechanic are speaking the same language, here is a list of some common "strange" car noise and their probable causes.

∑  Buzzing: Vibration of a loose fascia, vent, knob or wiring connector rattling against ductwork usually causes this bee-like noise. Debris in the ductwork also causes buzzing. High-pitched buzzing from under the vehicle usually means the heat shield on the catalytic converter is loose.

∑  Clicking: A metallic-sounding clicking noise that becomes more frequent as the throttle is applied may be caused by bent or loose fan blade hitting the radiator or protective shroud. This is especially true on older vehicles with metal fan blades.

∑  Clunking or thumping: A heavy, metallic sounding noise that usually happens as the vehicle is put into gear. On rear-wheel drive vehicles it can indicate a failing universal joint on the drive shaft. Also, check for loose items stored in the trunk.

∑  Grating or grinding: Metallic grating or grinding sounds occurring when the brakes are applied means worn brake pads or shoes. Good brakes are vital to vehicle safety. Get them repaired right away.

∑  Growling: On older vehicles, a growling sound coming from under the dash means a worn speedometer cable. In the engine, it can mean the crankshaft bearings are worn. Growling sounds may also be an indication of rear end problems.

∑  Hissing: If it sounds like air escaping, it probably is. Check the tires for a puncture or loose valve stem. Escaping steam from a blown radiator hose also hisses. When checking for steam, open the hood carefully. Steams burns can be nasty.

∑  Knocking: A metallic knocking sound like a hammer hitting a metal door could mean worn piston rod bearings, allowing the piston rod to knock against the inside of the engine, destroying it in minutes.

∑  Pinging: If the engine makes noises that sound like loose gravel in a tin can, you probably have pre-ignition, a condition caused by improper timing or by using the wrong octane fuel.

∑  Rattles: These can be caused by anything from a loose jack handle in the trunk to a broken or loose shock. Check for loose items before seeing the mechanic.

∑  Squeaks: Most squeaks are in the suspension system and are caused by a combination of road dirt and a lack of lubrication. Pressure wash the suspension and get a lube job. Spraying door seals with a Teflon lubricant will usually cure squeaking doors.

∑  Squealing or screeching: A loose drive belt can cause a high-pitched squeal under the hood. If the sound happens as the brakes are applied, the wear indicators are telling you the pads are worn.

∑  Tapping or ticking: A light metallic tapping or ticking sound may mean that the valves aren't getting proper lubrication or need adjustment.

∑  Whirring: A whirring, whirling sound may be an indication of pending automatic transmission trouble.

∑  Whistle: Caused by disturbed airflow around the vehicle, whistles can be difficult to pinpoint. Anything from a loose molding, antenna, mirror, roof rack or slightly open window can cause a whistle.

Peter duPre has been writing about cars and car care for over 30 years. He has authored automotive technical manuals and been published in numerous automotive magazines.

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