Crankshaft Bearing Inspection

Important:  All connecting rod and main journal bearings that have been used in a running engine must be replaced. Never re-use the crankshaft or connecting rod bearings.

The following bearing wear conditions should be used to diagnose engine operating conditions or root cause of a condition.

1. Inspect for fatigue indicated by craters or pockets. Flattened sections on the bearing halves also indicate fatigue.
Fig 1: Identifying Crankshaft Bearing Craters
Courtesy of GENERAL MOTORS CORP.
2. Inspect for excessive scoring or discoloration on both front and back of the bearing halves.
3. Inspect the main bearings for dirt imbedded into the bearing material.
   Fig 2: Identifying Crankshaft Bearing Scoring & Dirt

   Courtesy of GENERAL MOTORS CORP.
4. Inspect for improper seating indicated by bright, polished sections.
   Fig 3: Identifying Crankshaft Bearing Polished Sections

   Courtesy of GENERAL MOTORS CORP.