For 1990-2009 cars

## Drive Belt Diagnosis General

Noise | Definition
--- | ---
DEFINITION: The following are symptomatic noises and characteristics of the drive belt system. Multiple-ribbed drive belts wear evenly under normal conditions. Unusual wear and/or noise indicates a correction is needed.
Chirping |

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

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

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

Squeal |

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

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

Rumble |

• | A low pitch tapping noise caused by belt misalignment.

• | This noise occurs on cold start-up at idle.

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 belt.
Piling |

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

• | A small amount of piling is normal.

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

## Drive Belt Diagnosis Vibration w/ Electric Fan

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: The vibration is engine-speed related. The vibration may be sensitive to accessory load.
1 | Check the drive belt for wear, damage, debris build-up and missing belt ribs. Is the belt worn or damaged? | Go to Step 2 | Go to Step 3
2 | Replace as necessary. Refer to Drive Belt Replacement . Is the repair complete? | Go to Step 3 | --
3 | Check for loose or missing fasteners. Are there loose or missing fasteners? | Go to Step 4 | Go to Step 5
4 | Re-tighten or replace as necessary. Is the repair complete? | System OK | --
5 | Check for damaged or bent drive pulleys. Are there damaged or bent drive pulleys? | Go to Step 6 | Go to Step 7
6 | Repair or replace as necessary. Is the repair complete? | System OK | --
7 | Check for proper tensioner operation. Refer to Drive Belt Diagnosis Is the drive belt tensioner operating properly? | Go to Step 9 | Go to Step 8
8 | Replace as necessary. Refer to Drive Belt Tensioner Replacement . Is the repair complete? | System OK | --
9 | Check for loose, bent or cracked brackets. Are there loose, bent or cracked brackets? | Go to Step 10 | System OK
10 | Repair or replace the brackets as necessary. Is the repair complete? | System OK | --