| By Ann Arnott
What is your car trying to tell you?
A strange noise in your car can be like a pesky mosquito: Is it worth the time and effort to track it down?
Maybe it will go away. But maybe it's signaling trouble to come. Here is a list of some of the most common noises and what kinds
of problems they're likely to represent.
From The Engine
- "Hiss" or "Whistle" If it's noticeable mostly or only when the engine is running while the car is standing still, it's
probably a broken or missing vacuum hose. This is usually more of an annoyance than cause for serious alarm. But it
does create driveability problems, such as an engine that idles poorly, races or shakes, or has poor fuel economy.
Hissing when the steering wheel is turned right or left as far as it will go is normal.
- "Clatter-clatter" A light tapping or clicking that typically occurs when the engine hasn't been run for a while and
disappears after a few minutes usually is not a problem. It's caused by valve lifters that need time to refill with engine oil
upon starting.. Should the problem persist, check the oil level or consult a mechanic.
- "Squeal" If it's evident only while turning the wheels as you park or make low-speed turns (a sharp, jerky motion of the
steering wheel sometimes accompanies this sound), the power-steering belt is probably loose or worn. Tighten or
replace the belt. If it happens all the time or for a few minutes after starting the engine, other belts (alternator, water
pump, air-conditioner compressor etc.) may be loose. Adjust or replace as needed.
- "Thunk" or "clunk" during quick acceleration and deceleration (often accompanied by movement of the
console-mounted shift stick) means one or more badly worn or broken engine/powertrain mounts. Not a severe
problem, but it should be checked.
- "Ping" This noise which often sounds like marbles rattling in a metal container, usually comes when the engine is
straining during moderately heavy and heavy acceleration. It's caused by an abnormal engine-combustion condition
known as "detonation" or "spark knock". Switching to a higher-octane gas may cure it. Otherwise, see a mechanic.
Possible causes include carbon buildup inside the combustion chambers; vacuum leaks; a non-functioning
exhaust-gas recirculation (ERG) system or higher-than-normal engine temperatures. Excessive or prolonged pinging
could overheat key engine parts and lead to serious mechanical damage.
From The Brakes
- "Grind" or "scrape" A metal-on-metal sound each time brakes are applied is a sign of worn brake linings. Have a
qualified mechanic check the brake system as soon as possible.
- "Squeak" or "squeal" on braking could be a normal sound for some disc brakes. But it could indicate that brake
linings are greasy, glazed or worn. A programmed sound from a brake-wear sensor could be alerting you that it's time
to get the brakes checked. In either case, get them checked.
- "Tweet" or "chirp" during light or moderate braking, often diminishing or stopping during heavy braking, could be due
to loose-fitting brake pads in the caliper assembly. This is usually more of an annoyance that a safety problem and it
shouldn't be a terribly difficult job to correct.
From The Tires
The news here is good but deceiving, Tires (and cars) have become quieter, so sounds you think are coming from the tires may be
just normal road noise. And because tires have become much more dependable, flat tires are much less of a problem. A pull on
the steering wheel, in fact, is more likely to alert you to tire trouble than is a change in sound. Two noises to watch for, however:
- "Thump" One that increases and decreases as the vehicle speed changes could indicate flat spots on the tires or
broken belts inside the tires--not critical, but should be checked.
- "Hum" If it's similar to that of snow tires of years ago, it often indicates irregularly worn tires that are misalign or in
serious need of rotation.
Other Noises
- "Click" during sharp low-speed turns on a front-wheel drive vehicle usually signals worn constant velocity (CV) joints
on one or both half drive shafts. Have a mechanic check it out.
- "Grind" of rear wheels on front-wheel drive may mean that rear-wheel bearings need packing or replacing. Don't
ignore this symptom.
- "Roar" from under the car when accelerating probably comes from a hole in the muffler or exhaust pipes. Have the
system repaired immediately. Not only is this a traffic violation in many areas, but the hole allows poisonous
carbon-monoxide gas to escape--possibly into the passenger compartment.
What To Tell The Mechanic
The location or cause of a car noise can be deceptive. Be prepared to help the mechanic by being specific:
- Does the noise seem to come from one location, or does it "wander"?
- Is it constant or periodic?
- Did it develop suddenly?
- When do you hear the noise? At high speeds or low? When the engine is hot or cold? In a particular gear or while
shifting?
- How does it sound? Don't be afraid to mimic the noise.
- Stop short, however, of saying "It must be coming from the ______." Let the mechanic diagnose the cause. Your
diagnosis not only may be wrong, but it may send the mechanic off in the wrong direction.
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