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The bore in the cylinder head for the N3 EUI is directly through the cylinder head water jacket. To prevent coolant from contaminating the injector and still maintain maximum cooling of the injector, a stainless steel tube is screwed into the injector bore. The tube has a O-ring installed to create a water and gas-tight seal. ‪

Note: It is recommended that the injector tube be replaced with new a O-ring at the time of engine over haul. The injector tube is reusable.

Note: Do not remove the injector tube for inspection unless a fault in the tube is suspected.

Removal of the Injector Tube

Perform the following steps to remove the injector tube: ‪

  1. Remove Rocker Shaft assemblies. Refer to section .
  2. Remove N3 injector. Refer to section .


    Engine coolant must be drained prior to injector tube removal. ‪

  3. Drain engine coolant.Refer to section .


    Do not use excessive force on the injector tube during removal, cracking of the injector tube may occur requiring replacement. ‪

  4. Install tool J 46904 into injector bore and align tool with slots in tube and turn counter clockwise to remove.
Inspection of Injector Tube

Inspect the injector tube as follows: ‪

  1. Inspect injector tube for cracks or defects. If defective replace injector tube.
  2. Clean injector tube threads with a fine wire brush, being careful not to abrade the cylinder head to injector tube sealing surface.
  3. Clean the injector tube interior sealing surface, a chemical solvent maybe used for cleaning interior sealing surface.

Installation of Injector Tube and Seal

Perform the following steps for injector tube installation: ‪

  1. Clean injector bore of debris.

    Note: Replace with new O-ring when injector tube is removed or replaced.

  2. Install O-ring in groove on injector tube, a small amount of silicone based O-ring lubrication will aid in the installation. See Figure 44021 .

    Injector Tube and O-ring

  3. Coat the threads of injector tube with a high temperature nickel based antiseize lubricant.
  4. Install the injector tube on tool J 46904. See Figure 43801 .

    Installation of Injector Tube on Tool J 46904

  5. Using tool J 46904 install injector tube in injector bore. See Figure 43802 .

    Installation of Injector Tube in Cylinder Head

  6. Torque injector tube to 35-45 Nm (26-33 lbft).
  7. Release torque approximately 180 degrees.
  8. Torque injector tube to 35-45 Nm (26-33 lbft) ensure the tip of the injector tube is flush or below the fire deck, the tube should not protrude.