When to Rebuild Your Caterpillar C15 Diesel Engine

Diesel engines are built to lastyou can run them for miles and miles. But, eventually, you're going to have to rebuild that engine.

Regular maintenance is the key to keeping your diesel engine running and on the job, but if you notice a drop in performance, along with a number of additional issues, you may be ready for a new rebuild kit. 

If you're wondering what you should watch for if you're running a CAT C15 diesel engine we're bringing you the main symptoms that may be present when it's time for a rebuild.

You can also watch our video to learn more:



Curious about preventive maintenance? Check out our blog on how proper maintenance inspections can save you money!

We've got rebuild kits for your diesel engine! Our ASE Certified Technicians can help you find the right kit for your job!

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Symptoms Your C15 is Ready for a Rebuild


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Watch out for these symptoms to know if it might be time to rebuild your Caterpillar C15 engine:

  • Crankcase pressure or blowby
  • Oil consumption
  • Knocking
  • Excessive smoke
  • Loss of compression
  • Poor fuel economy
  • Oil sludge

Some of these symptoms are related to each other, so it's likely that you'll be experiencing more than one of these. For example, you might have compression issues if you notice that you have lower power than normal and worse fuel economy. Your engine also might be running rougher, have blowby, or you might have white smoke. So, as we've mentioned in other posts, it's important to diagnose the overall issue with your engine to make sure you're fixing the problem with your repair. 

If you want to know more about what to do about compression issues, check out our compression issue failure analysis

Worried about a diesel engine other than a C15? We've got a list of general signs that your engine might need a rebuild!


What Can I Test for on My C15?

If you're worried about the overall health of your CAT C15, there are a few things that you can test for. 

First, you can do an oil analysis. When you do this, you want to look for high metal concentration, foreign contaminants, or unfiltered air entering your system.

You also can check for excessive blowby. This is due to piston and ring wear, causing higher than normal oil consumption. It can also include any of the turbo, worn valve guide, or cylinder head issues. They're all symptoms that you may be ready for an overhaul.

Additionally, look at the date of your past rebuild for some insight. If it's been a while, it might be time to consider another rebuild.

Are you experiencing excessive oil consumption? Read our post explaining high oil usage to find out why!


What Rebuild Kit is Right for My C15?

If you've decided that a rebuild is the right option for your Caterpillar C15 diesel engine, then you'll be in the market for a new rebuild kit. We offer both an inframe and an out-of-frame overhaul kit in the 2250115-C15, as well as a re-ring, the IFC15E1. 

What's the difference between an inframe, out-of-frame, and re-ring kit?

Well, it all comes down to the kit contents. The re-ring kit it the smallest rebuild kit option and will take you the least time when it comes to the actual rebuild. Your pistons have to be reusable for this to be a valid option for you.

An inframe kit is just what it sounds likeit means you can complete the rebuild inframe. This kit option comes with more components (like new pistons) and will be a more time-consuming job.

Finally, you have the out-of-frame kit. This comes with more components than the other two kits and is the most labor-intensive job. But, since most of your components are being replaced, you know you'll have even wear across the engine.

Need more information before you decide? Read our blog, How to Choose an Engine Rebuild Kit.


Whether you like it or not, there will come a time when you need to rebuild your diesel engine. We're here to help you get everything you need to make the job as easy as possible!

In the market for a rebuild kit? Our ASE Certified Technicians can help you find what you need! Give us a call at 844-304-7688, or request a quote online!