Drive Belt: Testing and Inspection

The following are symptomatic noises of the accessory drive belt system:
1. 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.

2. 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.

3. Whine: A high pitched continuous noise that may be caused by a failed component bearing.
4. Faint Cycle Rumbling: A low frequency noise heard once per revolution of the belt.
5. Pilling:
^ The random accumulation of rubber dust in the bottom of the multi-ribbed belt grooves.
^ A small amount of pilling 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.

Multiple ribbed, accessory drive belts wear evenly with their pulleys. Unusual wear indicates a correction is needed. The following diagnostic tables will aid in diagnosing drive belt system problems.





DRIVE BELT DIAGNOSIS





DRIVE BELT SQUEAL





DRIVE BELT WHINE





DRIVE BELT RUMBLING








DRIVE BELT FALLS OFF





DRIVE BELT DIAGNOSIS