Pilling

In this case, the belt grooves become worn and subject to abrasion.

Cause:

There are various causes of pilling, including misalignment between the idlers, new belt running over worn idlers, excessive tension, or a combination of these factors. This fault often occurs in diesel engines.

Solution:

When pilling in the belt causes excessive belt vibration, the belt should be replaced. Make sure the new belt is properly seated on the idlers. Check the tension and ensure proper belt tension on the tensioner belt is aligned.