Uneven Rib Wear

Excessive wear on one groove compared to the others, or a groove that has a different wear pattern than the others. A knocking or grinding sound may also be heard.

Cause:

A foreign object, such as a pebble, in the pulley causes uneven wear and can damage the belt and tear the inner threads of the belt. Cars with damaged engine guards are more likely to have this problem.

Solution:

Replace the belt and make sure the new belt is properly seated on the pulley. Install the motor guard.