Grand Prix V6-3.8L SC VIN 1 (1997)
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.
NOTE: 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.