Drive Belt: Testing and Inspection

DEFINITIONS
The following are symptomatic noises of the drive belt system:

Chirping
The following items are indications of chirping:
^ A high pitched noise that is ususally 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
The following items are indications of squeal:
^ A loud screeching noise that is caused by a slipping belt (This is unusual for a belt with multiple ribs.)
^ 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.

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

Faint Cycle Rumbling
A low frequency noise heard once per revolution of the drive belt.

Pilling
The following items are indications of 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.

Multi-ribbed type drive belts wear evenly with their pulleys. Unusual wear indicated a correction is needed. The following diagnostic tables will aid in diagnosing drive belt system conditions.