How to Replace Duramax Injectors

by James Marshall

The Duramax engine is an eight-cylinder diesel engine from General Motors that has been in production since 2001. General Motors uses it in larger trucks, such as the Chevrolet Silverado 2500 and 3500. The Duramax employs fuel injection to deliver fuel to the engine under very high pressure. The procedure for replacing the fuel injectors is generally the same for all full-size Chevrolet trucks made after 2005 with diesel engines.

Step 1

Drain the coolant from the radiator into a container, and seal the container for later use. Remove the cable from the negative battery terminal with a socket wrench. Detach the electrical connector for the air inlet duct from the left side of the turbocharger. Remove the electrical connectors from the main wiring harness on the engine. Disconnect the electrical connector from the barometric sensor.

Step 2

Remove the clip on the engine wiring harness, and disconnect the bracket for the harness with a socket wrench. Detach the electrical connector for the glow plug controller, and remove the positive crankcase ventilation hose from the crankcase.

Step 3

Disconnect the outlet duct for the air cleaner on the right side of the engine with a socket wrench. Release the clamp on the hose to the outlet duct, and disconnect the hose from the outlet duct. Remove the fuel filter and its bracket from the engine. Disconnect the control module from the fuel injectors.

Step 4

Blow debris away from the fuel injectors and fuel lines with compressed air. Clean the fuel lines and fittings with a clean shop cloth. Remove the fuel lines from the fuel injectors and disconnect the electrical wiring from the fuel injectors.

Step 5

Remove the mounting bolts for the fuel injector bracket with a socket wrench. Connect injector removal tool J-46594 to the bolt hole on the fuel injector bracket. Pull the injector removal tool away from the fuel injector with a flare nut wrench to remove the fuel injector. Disconnect the injector removal tool from the fuel injector. Replace the copper washer and O-rings on the fuel injector if necessary.

Step 6

Install the new fuel injector, and fasten the mounting bolts for the fuel injector bracket by hand. Tighten the mounting bolts to 22 foot-pounds with a torque wrench. Attach the electrical wiring for the fuel injectors. Connect the fuel lines to the fuel injectors, and attach the clips to the fuel lines. Tighten the retaining nuts for the fuel lines to 30 foot-pounds with a torque wrench.

Connect the remaining components by performing steps one through three in reverse order. Replace the coolant in the radiator.

Items you will need

  • Socket wrench set
  • Shop cloth
  • Air compressor
  • Injector removal tool J-46594
  • Flare nut wrench

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