Piston Rings Failure Analysis

Are you experiencing piston ring failure, but aren't sure what might have caused it? 

There are several issues that might lead to your piston rings failing, so it's important to properly diagnose the issue to correct it. 

This failure analysis takes you through possible issues that may have caused your piston rings to fail.

Need some new pistons due to a failure in your diesel engine? Our ASE Certified Technicians can help ensure you're getting the right parts for your engine.

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Broken Oil Control Ring Caused by Assembly Error

One common problem we see is assembly error. This can lead to issues with your oil control ring.

The following picture shows the broken oil control ring positioned on a flat, granite surface. Note the upward bend on the broken side of the ring.


Broken Oil Control Ring | Highway & Heavy Parts
The cause of failure would be the ring not being sufficiently compressed, and it was damaged during installation. 

High Crankcase Pressure Caused by Rings Not Installed Correctly

Again, proper installation is key to successfully operating piston rings.
Rings not installed correctly allow a combustion path to the crankcase, causing high crankcase pressure— “blow by”—and loss of power.


Piston Problems | Highway & Heavy Parts



High Oil Consumption Caused by Broken Oil Control Ring

If you're having trouble with high oil consumption, it's possible that your oil control ring is broken.

The picture shows the oil control ring broken in several areas (yellow arrows). The most likely cause of failure would be that the ring was damaged during installation.


Damaged Oil Control Ring | Highway & Heavy Parts


A broken oil control ring isn't the only thing that can cause excessive oil consumption. Read our post explaining high oil consumption to learn more. 

Ring Failure Caused by Abrasive Contamination

Claim: Excessive oil consumption

Observations: 4 ring sets were examined for possible cause of excessive oil consumption. The top compression ring and intermediate rings were examined under magnification. During the inspection process, noticeable vertical scratching of the ring faces was found. Scratching of the ring faces will cause incomplete sealing of the power cylinder, and can cause excessive oil consumption. 

Possible causes of this type of condition:

  1. Leaks in the air intake system.
  2. Abrasives in the engine oil.
  3. Poor cleanliness during assembly.

No manufacturer defects were observed in the inspection process.


Excessive Oil Consumption | Highway & Heavy Parts

Overall, it's important to have your piston rings operating correctly to prevent other problems in your diesel engine.

For more information on problems with pistons, check out our piston quick seizure reference guide.


Need a set of replacement pistons? Give our ASE certified technicians a call at 844-304-7688, or request a quote online!

Originally Posted November 19, 2015; Edited April 10, 2020