Caterpillar Diesel Engine Serial Numbers


dataplate on a caterpillar engine | Highway & Heavy Parts


If you're shopping for parts for your Caterpillar diesel engine, then you're going to want to make sure that you're getting the right ones the first time. To help us get you exactly what you need, you need to have your engine serial number handy. 

Where is that, you ask? Well, we're going to take you through where you should be looking to find this information on your CAT engine. Read on to find out more!

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Where Do I Find My Caterpillar ESN?

Most engine serial numbers can be found on the dataplate, which is typically on the driver side of the valve cover. Not all engines are consistent in where they put these information plates. The dataplates for a certain type of engine can be found in various places depending on the model. However, Caterpillar is pretty regular with their location.

If you're looking for more information on ESNs in general, we have a blog about other diesel engine serial numbers!

Want all the info on your Caterpillar ESN? Download this free quick guide!

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What's the Format of a Caterpillar Engine Serial Number? 

Its a little hard to find something when you dont know what youre looking for. We get people that try to give us part numbers, casting numbers, or even VINs instead of ESNs, simply because they dont know what an engine serial number should look like.

All Caterpillar ESNs have a similar format, which makes them pretty easy to identify. They all begin with a three number/letter prefix, which is then followed by 7 digits.

The prefixes will correspond to a particular model, and usually to a certain subsets of the model. For the more popular prefixes, people will sometimes refer to their engine by the prefix rather than the broader model. You may have heard someone say, Oh, yeah, my 6NZ runs like a champ. A 6NZ is a common prefix for a single-turbo C15. Some prefixes even have reputations. For example, a C15 with a prefix of MBN is known as a Bridge motor (because it was the bridge engine from the mechanical C15 to the electronic C15 ACERT), and is often heavily criticized.

If you want to know more about one of CAT's most popular engines, check out our Caterpillar 3406E Engine Spotlight!


Caterpillar ESN Prefixes by Model


  • 92U


  • 2EK
  • 3ZJ
  • 4CK
  • 4MG
  • 5KJ
  • 7FB
  • 8TC


  • 3ZJ
  • 4CK
  • 5KJ
  • 8PN


  • 1LW
  • 2WS
  • 5DS
  • 5EK
  • 6TS


  • KAL
  • C7S


  • 1YN
  • 2KS
  • 8YF
  • 9NS
  • 9SM
  • CPD
  • GEP
  • MBL
  • TME

C15 and C15 ACERT:

  • 6NZ
  • 9NZ
  • B5R
  • BXS
  • EGH
  • JEP
  • KRA
  • MBN
  • MXS
  • NXS
  • RKS
  • SDP
  • TRB


  • 7CZ


Why is My Caterpillar Engine Serial Number Important? 

As much of a pain as it can be to find and identify your ESN, its incredibly important that you do it when you go to order parts. Giving us your engine serial number will guarantee you get the right parts for your engine, because we can look it up to figure out what your engine was originally built with.


inputting your esn on the website when buying a part | Highway & Heavy Parts


You will see that when you enter some of our product pages, there is a box under our price with the available options. One option field that appears is for your Engine Serial Number. While youll be able to place an order without inputting your ESN, you will get a call from us asking for it before we will actually be able to get your order processed. And that just slows everything down.

Got questions? We've got answers! Our ASE Certified Technicians can help you with your diesel engine part needs. Give us a call at 844-304-7688 if you have any questions! Or, you can request a quote online.

Originally Posted October 4, 2017; Edited December 3, 2019