Failure Analysis: How Can My Crankshaft be Bent?

It keeps your engine moving and is vital to the overall health of your rig. So when something goes wrong with your crankshaft, the results can be disastrous. One cause of crankshaft failure is a bend or distortion in the part. It's important to know how this occurs and the impact it has on your engine.


A Crankshaft Failure Analysis 

Detroit Diesel Series 60 12.7L Crankshaft, New | Highway & Heavy Parts

Wondering if your crankshaft might be the cause of your diesel engine troubles? In this post, we're taking you through the causes of a bent crankshaft and what that can mean for your engine.


Do you have any questions about your diesel engine crankshaft? Give our ASE Certified Staff a call!

Give Us A Call!


What Can Cause My Crankshaft to Bend? 

There are several factors to consider when looking for the cause of a bent crankshaft. Some possible causes might be:

  • Extreme heat or alternating heating and cooling resulting in a distorted crankshaft. The heat causes expansion and the cooling causes contraction. Repetition over time can lead to a bend.
  • If there is a bearing failure, extra clearance will be created and the crankshaft will move around more freely in the engine. Not only will this lead to a bend in the crankshaft, it also causes damage to other components, requiring a more extensive fix than just replacing the crankshaft. This means more money out of your pocket.
  • Certain operating conditions can cause the crankshaft to bend, such as lugging or over-speeding.
  • Dropping the crankshaft or other improper handling techniques before or during installation can also distort your crankshaft. To learn more about proper crankshaft installation, read our previous blog.

What Can a Bent Crankshaft do to My Engine? 

One of the biggest issues a bent crankshaft can cause is excessive wear on your main bearings. The bend decreases oil clearance and allows for the wear to occur. The below image shows the wear pattern caused by a bent crankshaft.

Bearing Wear From Distorted Crankshaft | Highway & Heavy Parts

As you can see, the largest amount of wear is on the center bearing, indicating that the greatest distortion was in the center of the crankshaft.

Not sure if the crankshaft is the cause of your diesel engine failure? Check out our list of common diesel engine problems


Can Anything Cause Similar Problems?

Similar issues may arise from a distorted crankcase, which can also be caused by heating and stressful operating conditions, but also incorrect torqueing during installation. As we've mentioned in other posts, diagnosis is key to a proper repair. You want to make sure you're addressing the entire issue, not just putting a band-aid on it. This will help prevent continued failure. 

At Highway & Heavy Parts, we're dedicated to taking the risk out of buying parts. Let us help you find the best diesel parts for your engine!


If you think you might be experiencing issues due to a bent crankshaft, call our certified staff at 844-304-7688. You can also visit our crankshaft page, or request a quote online.


Originally Posted September 18, 2018; Edited December 10, 2020