Piston Skirt Failure Analysis

 Have you taken your diesel engine apart and noticed damage to your piston skirts?

You might be wondering what could cause this kind of failure. We're taking you through possible failure modes to help prevent this damage from occurring on your pistons again. 

Do you find yourself in need of new pistons for your diesel engine? We have ASE Certified Technicians on staff who can help you get exactly what you need!

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Need to replace your diesel engine pistons? Learn whether reusing your pistons could work for your engine. 

Piston Skirt on Upside Down

 The following picture shows the piston skirt in the liner with the skirt on upside down. Red arrows point to bottom of skirt.


Piston skirt upside down failure | Highway & Heavy Parts


The next picture shows the bolts broken in the piston pin and the top of the piston skirt pointing down. 


Piston pin broken bolts |Highway & Heavy Parts
Conclusion: The cause of failure is assembly error. Piston skirts were installed upside down on the pistons. When installed in this manner the skirt can make contact with the crankshaft throws. This will place excessive loads on the connecting rod retaining bolts, causing them to fracture. 

Piston Skirt Scuffing Caused by a Low Coolant Level

The following pictures show scuffing on piston skirts. The first two pictures show light scuffing on the major thrust side of the skirt and only a few scratches on the minor side.

Light Scuffing on Piston skirts | Highway & Heavy Parts
The next picture shows both sides of the piston. As you can see, there is heavy scuffing all around the outside of the piston.

Heavy Scuffing Piston Skirts | Highway & Heavy Parts

The final picture is the inside of the liner. It shows 360 degree scuffing on the upper half of the liner and the quarter point on the lower half. The liner is upside down in this picture.

360 degree scuffing on piston skirt | Highway & Heavy Parts

Conclusion: Both failures are caused by overheating. The most likely cause of the scuffing is low coolant.
Piston skirts aren't the only part of the piston that can fail. Other components associated with your diesel engine pistons can cause problems as well.  Check out our post on piston cooler failures
At Highway & Heavy Parts, we have a large selection of replacement pistons for your diesel engine. Let us help you keep your engine running!

If you're looking for replacement pistons for your diesel engine, our ASE Certified Technicians are ready to help you get the right parts for your application. Call them at 844-304-7688, or request a quote online!

Originally Posted November 18, 2015; Edited April 3, 2020