Recently in this column we discussed various booms, buzzes and other noises often heard in cars. We asked automotive repair specialists Jeffrey Boone and Ed Kriston from the Towson office of AAA Mid-Atlantic, based in Wilmington, Del., to offer guidelines about other commonly heard sounds that often emanate from cars. Consider the answers the next time you hear one of these noises:
Scrape and screech when braking
» Guidelines: The only time a sound may be inconsequential is first thing in the morning. The noise is likely caused by moisture on the rotors. If the sound occurs at other times, it may be due to a variety of issues including rust on the rotors. Other noises may indicate the brakes need adjustments. Thumping may indicate a warped rotor or brake drum.
» First step: Test the brakes by driving in reverse and applying them. If you still hear the sound, take the car to an approved auto technician.
Reduced noise as the engine hesitates
» Guidelines: While this was easy to diagnose in the past, today?s sophisticated motors make it more challenging.
» First step: This is a circumstance where you want to go to a technician with special knowledge of your auto make. A General Motors car may have a very different fix than that of a Mercedes-Benz.
Whirring akin to an airplane taking off
As a rule, this happens only on rear-wheel vehicles.
» Guidelines: When a bearing starts to go bad, be it from a water pump or alternator, it will make that noise.
» First step: Take the car to an approved auto technician to determine the cause.
Rattling from underneath the car
» Guidelines: A broken exhaust is nothing to ignore. Not only is it annoying to other drivers, but it is dangerous. Fumes emitted can seep into the car and harm the driver.
» First step: Have the exhaust replaced as soon as possible.
Hiss
» Guidelines: Generally this is caused when a windshield or trim is unsealed. It could also be caused by a vacuum leak. The wind interference causes the car to run poorly.
» First step: Listen to identify the origin of the noise and convey it to your auto technician.
Ping
» Guidelines: Generally this comes from under the hood and is due to a poor grade of gas. If a car has been parked for an extended period of time, the ping could be caused by a low octane level.
» First step: Top off the vehicle with high octane gas. If the sound continues, the car may need a fuel injection cleaning.
