Auto Noise – Squealing Sounds
by John Mosko

General Description of Problem:
You hear a squealing sound at some point during the operation of your vehicle.

Probable Explanation:
Most squealing in an automobile comes from one of two locations. These are the belts or the brakes. Typical squealing from under the hood occurs when belts are slipping while brakes often squeal when either engaged in stopping or when the pads are worn to a low level and the “Warning Sensor” squeals to notify you it is time to get your brakes replaced.

Solutions:
1. Determine if the squeal is under the hood or in the brake system. Common under the hood squeals can be heard immedietely after starting the car as the various belts kick into action, during use of the A/C system, or while turning in a car with power steering. If the squeal is only noticeable while braking, or is only heard while the car is in motion but disappears when braking, the squeal is likely from the brake system.

2. Once you have determined the belt that is the cause of your squeal, you will need to check it for tightness, and replace if it is worn. As mentioned above, common belts that squeal are the power steering belt if you hear the noise during turns, and the A/C belt if the noise is noticeable only when the A/C is on. Other belts to consider are the alternator belt if you hear the sound under load or acceleration, or if under idle it may be the timing belt.

3. If the noise is not coming from the belts, you will want to determine wheteher the sounds from the brake system are during stopping, or during travel. If you hear the squeal only when applying the brakes, this may be an annoyance more than a problem. If you depress the pedal lightly and hear a faint squale, you can likley obtain some anti-squeal brake paste to apply to the pads to minimize the noise. If you get the squeal when braking hard as well, you may need a different type pad or lining than what is currently installed. If you notice the noise while driving and it disappears when you step on the brakes, this is most likely caused by the sensors on your current pads rubbing and emitting the noise to notify you it is time to have your brake pads replaced.