Rod Bearing Failure Analysis
Did you just hear that the rod bearings in your diesel engine have failed? Are you wondering how exactly that could have happened?
We're taking a look at what might have gone wrong in your diesel engine to cause a rod bearing failure. Keep reading for an in-depth failure analysis.
Has a diesel engine failure left you in the lurch? Our ASE Certified Technicians are ready to help you get the replacement parts your need for your repair!
Want more information on your rods and rod bearings? Be sure to read our connecting rod failure analysis!
Bearing Failure Caused by Foreign Material on the Back of the Bearing
One of the main causes of rod bearing failure is the presence of foreign material on the bearing itself.
The next two pictures show a rod bearing with a piece of tape or paper on the back of the bearing where it seats in the connecting rod (blue arrow); the pattern of the tape is clearly visible on the front side of the bearing where it came in contact with the crankshaft connecting rod journal (green arrow).


Bearing Failure Caused by Excessive Wear in Support Components
Additionally, your rod bearing failure can be caused by excessive wear in the support components. The pattern on the rod bearings indicate either a barrel shaped crankshaft or distorted and worn connecting rod bores.

Bearing Failure Due to Worn Crankshaft or Out of Round Connecting Rods
The final picture shows the uneven wear patterns on the rod bearings. Gouges in the bearings are caused from abrasive contamination not properly removed from the engine during overhaul.

Conclusion: The bearings have uneven wear spots most likely caused by either a worn crankshaft or out of round connecting rod bearing bores. One bearing had a piece of tape on it that was between the bearing and the rod bearing surface. The pattern of the tape was clearly visible on the reverse side of the bearing.
Cylinder Kit Failure from Lack of Proper Lubrication
Another possible cause of failure is a lack of lubrication in your diesel engine. The pictures below show what this can look like.





Are you in need of diesel engine replacement parts? Our ASE Certified Technicians can help you get the right parts for your repair job. Call them at 844-304-7688, or request a quote online!
Originally Posted November 18, 2015; Edited March 30, 2020