Visual Diagnosis

Fig 1: Belt Wear Patterns

Courtesy of DAIMLERCHRYSLER CORP.

When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface (1) of the belt from rib to rib, are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (2) (not across) are See Fig 1.not  normal. Any belt with cracks running along a rib (2) must be replaced. Also replace the belt if it has excessive wear, frayed cords or severe glazing.