How to Remove the Fuel Injectors From a Caterpillar Diesel Motor

Updated July 20, 2017

The fuel injectors inside of a Caterpillar diesel engine are the main components that supply the diesel to the cylinder heads. The diesel sprays out of the nozzle that is attached to the bottom of the fuel injector. If the nozzle becomes clogged by impurities from the diesel or a small piece of debris, the nozzle will not be able to spray the fuel evenly into the cylinder. Once the fuel injector becomes clogged up, remove the valve cover and replace it as soon as possible.

Remove the bolts from both valve covers with a ratchet, extension and a socket. Pull the valve covers off and place them in a safe area.

Loosen and remove the bolts that are holding down each section of the rocker arm assembly with a ratchet and a socket until all of the bolts have been removed from the assembly. Pull the rocker arm assembly out and place it in a safe area.

Beginning with one of the fuel injectors, remove the 5mm hold-down bolt that holds the fuel injector to the cylinder head with a ratchet and a socket. Place the bolt in a safe area.

Remove the fuel line that is attached to the top of the fuel injector with a open end wrench for screw-on fuel lines or pliers for rubber fuel lines.

Place the end of the CAT fuel injector removal tool over the fuel injector. Secure the tool to the base of the fuel injector. Slowly move the fuel injector tool back and forth while pulling up on the tool at the same time until the injector comes out of the cylinder head. Place the fuel injector to the side and repeat the same process to remove the other fuel injectors.

Install the new fuel injectors by pushing each injector into each cylinder head with the fuel injector tool or with your hands until the injectors are seated inside of each hole. Each fuel injector has a rubber seal around the base of the injector. Ensure that the rubber seal is seated inside of each hole.

Reinstall the fuel lines to each injector, the rocker arm assemblies and the valve covers to finalise the process.


The proper type and size CAT fuel injector removal tool can be found at a CAT dealership or at most all major truck repair shops.


Ensure that the engine is completely cooled off before removing the fuel injectors. Working on or around a hot engine can result in serious burns.

Things You'll Need

  • 1/2-inch drive ratchet
  • 1/2-inch drive socket set (Metric)
  • Open end wrench set (Metric)
  • Pliers
  • CAT fuel injector removal tool
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About the Author

Kevin Mclain has more than 20 years of automotive, home improvement and landscaping experience. He has been writing for various online publications since 2002. Mclain has U.S. Army certification in automotive maintenance and repair, among more than 15 additional certifications related to the automotive field.