It could also be caused by a vacuum lead

, to offer cv axe guidelines about other commonly heard sounds that often emanate from cars.

</section>. Consider the answers the next time you hear one of these noises:

Scrape and screech when braking

» Guidelines: The only time Wheel Bearings a sound may be inconsequential is first thing in the morning.

» First step: Have the exhaust replaced as soon as possible.

» Guidelines: When a bearing starts to go bad, be it from a water pump or alternator, it will make that noise. If the sound occurs at other times, it may be due to a variety of issues including rust on the rotors.

Reduced noise as the engine hesitates

» Guidelines: While this was easy to diagnose in the past, today?s sophisticated motors make it more challenging.

Recently in this column we discussed various booms, buzzes and other noises often heard in cars.
If the sound continues, the car may need a fuel injection cleaning. If you still hear the sound, take the car to an approved auto technician.

Rattling from underneath the car

» Guidelines: A broken exhaust is nothing to ignore. Other noises may indicate the brakes need adjustments. We asked automotive repair specialists Jeffrey Boone and Ed Kriston from the Towson office of AAA Mid-Atlantic, based in Wilmington, Del.

» First step: Top off the vehicle with high octane gas.

» First step: Take the car to an approved auto technician to determine the cause.

Hiss

» Guidelines: Generally this is caused when a windshield or trim is unsealed. Not only is it annoying to other drivers, but it is dangerous.

Ping

» Guidelines: Generally this comes from under the hood and is due to a poor grade of gas.
It could also be caused by a vacuum leak. Thumping may indicate a warped rotor or brake drum.

» First step: This is a circumstance where you want to go to a technician with special knowledge of your auto make. If a car has been parked for an extended period of time, the ping could be caused by a low octane level. A General Motors car may have a very different fix than that of a Mercedes-Benz. The noise is likely caused by moisture on the rotors. Fumes emitted can seep into the car and harm the driver.

» First step: Listen to identify the origin of the noise and convey it to your auto technician.

» First step: Test the brakes by driving in reverse and applying them.

Whirring akin to an airplane taking off

As a rule, this happens only on rear-wheel vehicles. The wind interference causes the car to run poorly