For 1990-2009 cars

### Drive Belt Dressing

Do not use drive belt dressing (adhesion enhancement chemical) or any other chemical on the drive belt(s).

### Drive Belt Noise

Drive belt noise may be described as a thumping noise heard at, or just above idle speed, as a result of drive belt pilling. In a single-belt drive, drive belt pilling occurs when small particles of drive belt material separate from the drive belt grooves, and form small balls or pills in the drive belt grooves. While some drive belt pilling is normal, excessive pilling can cause a thump or knocking as the pills pass over various drive belt pulleys. This causes the drive belt to repeatedly jump off of and slap onto the drive belt pulley.

The thump or knocking noise easily misdiagnoses as an engine noise. In order to diagnose drive belt pilling, adhere to the following procedure:

1. Remove the drive belt.
2. Run the engine for no more than 30 to 40 seconds, in order to confirm that the engine noise disappears.
3. Inspect the power steering pulley for proper alignment.
4. Inspect all other pulleys for excess paint, debris or pills in the grooves.
5. Clean the pulleys with a wire brush, as necessary.

### Definitions

The following are symptomatic noises of the drive belt system:

#### Chirping

• | A high pitched noise that is usually heard once per revolution of a drive belt pulley or a drive belt.

• | It is most common on cold, damp mornings.

• | Verify this condition by squirting water onto the drive belt. The noise will momentarily stop.

#### Squeal

• | A loud screeching noise that is caused by a slipping drive belt (this is unusual for a multi-ribbed drive belt).

• | The noise occurs when a heavy load is applied to the drive belt, such as an air conditioning compressor engagement, snapping the throttle, or slipping on a seized drive belt pulley.

#### Whine

A high-pitched continuous noise that may be caused by a failed component bearing.

#### Faint Cycle Rumbling

A low-frequency noise heard once per revolution of the drive belt.

#### Pilling

• | The random accumulation of rubber dust in the bottom of the multi-ribbed drive belt grooves.

• | A small amount of pilling is normal.

• | Operation of the drive belt system will not be affected unless the buildup exceeds one third (1/3) of the drive belt groove depth.

Multi-ribbed drive belts wear evenly with their drive belt pulleys. Unusual wear indicates a correction is needed.