GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Electrical 🢒 Valve Rocker Arm Cover Replacement - Upper Left Side

Removal Procedure
  1. Remove air cleaner layer. Refer to Air Cleaner Replacement in Engine Controls - 6.6L.
  2. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim.
  3. Remove the charged air cooler inlet duct to turbocharger charge air cooler outlet.
  4. Remove the nut retaining the battery cable to the generator.
  5. If equipped, remove the battery cable to the auxiliary generator.
  6. Remove the battery cable harness clip from the bracket.
  7. Move and secure the battery cables out of the way.
  8. Disconnect the fuel hoses. Refer to Metal Collar Quick Connect Fitting Service in Engine Controls - 6.6L.

    9. Object Number: 674653 Size: SH
  9. Disconnect the fuel injection control module wiring harness connectors. Lift up on the latch in order to disconnect the connectors.
  10. Remove the fuel injection control module wiring harness clip from the bracket.

    11. Object Number: 674680 Size: SH
  11. Remove the bolts (1) retaining the fuel injection control module wiring harness connectors.
  12. Remove the bolts (2) retaining the fuel injection control module wiring harness bracket.
  13. Remove the water outlet tube. Refer to Water Outlet Tube Replacement in Engine Cooling.
  14. Remove the glow plug relay bracket. Refer to Glow Plug Relay Replacement in Engine Controls - 6.6L.
  15. Remove the fuel filter/heater element housing. Refer to Fuel Filter Assembly Replacement in Engine Controls - 6.6L.
  16. Remove the auxiliary generator, if equipped. Refer to Auxiliary Generator Replacement in Engine Electrical.

    17. Object Number: 687021 Size: SH
  17. Disconnect the PCV hose from the upper valve rocker arm cover.
  18. Remove the fuel injector lines.

    19. Object Number: 665256 Size: SH
  19. Remove the 11 bolts retaining the upper valve rocker arm cover.

    20. Important: The valve rocker arm cover uses sealer. Pry only at the locations shown. Avoid damage to the sealing surfaces.

  20. Using a gasket scraper or other suitable tool at the prying locations, loosen the upper valve rocker arm cover.

    21. Object Number: 660467 Size: SH
  21. Remove the upper valve rocker arm cover.

    22. Object Number: 663628 Size: SH
  22. If replacing the upper valve rocker arm cover, remove the grommets for the injector line fittings.

    23. Object Number: 663733 Size: SH
  23. If replacing the upper valve rocker arm cover, remove the screws, PCV diaphragm, and spring.
  24. Inspect the PCV diaphragm for damage.
  25. Replace the PCV diaphragm if damaged is found.
  26. Clean the sealer from the sealing surfaces on the upper valve rocker arm cover and the lower valve rocker arm cover.
  27. Clean the upper valve rocker arm cover in suitable cleaning solvent.
  28. Inspect for cracking and other damage on the upper valve rocker arm cover.
  29. Replace the upper valve rocker arm cover if any damage.

Installation Procedure

    Object Number: 663733 Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  1. If removed, install the PCV diaphragm, spring, cover, and screws.

    2. Tighten
    Tighten the PCV cover screws to 4 N·m (35 lb in).


    Object Number: 663628 Size: SH
  2. If removed, install NEW grommets for the injector line fittings.

    3. Object Number: 665277 Size: SH
  3. Apply a 2-3 mm (1/8 in) wide to 0.5-1.5 mm (1/16 in) high bead of sealant GM P/N 12378521 or equivalent to the upper valve rocker arm cover sealing surface.
  4. Apply a bead of sealant GM P/N 12378521 or equivalent to the area under the injector wire harness on the lower valve rocker arm cover.

    5. Object Number: 660467 Size: SH
  5. Install the upper valve rocker arm cover.

    6. Object Number: 663904 Size: SH
  6. Install the upper valve rocker arm cover bolts.

    7. Use the bolt tightening sequence. Bolts number 1 and 2 are used to position the valve rocker arm cover.

    Tighten

    1. Tighten the upper valve rocker arm cover bolts to 8 N·m (71 lb in) in the sequence shown.
    2. Tighten the upper valve rocker arm bolts again to 8 N·m (71 lb in) in the sequence shown.
  7. Install fuel injector lines.

    8. Tighten
    Tighten the fuel injector lines to 41 N·m (30 lb ft).


    Object Number: 687021 Size: SH
  8. Connect the PCV hose to the upper valve rocker arm cover.

    9. Object Number: 674680 Size: SH
  9. Install the bolts (2) retaining the fuel injection control module wiring harness bracket.

    10. Tighten
    Tighten the wiring harness bracket bolts to 10 N·m (89 lb in).

  10. Install the bolts (1) retaining the fuel injection control module wiring harness connectors.

    11. Tighten
    Tighten the fuel injection control module wiring harness connector bolts to 21 N·m (15 lb ft).


    Object Number: 674653 Size: SH
  11. Connect the fuel injection control module wiring harness connectors.
  12. Install the fuel injection control module wiring harness to the retainer.
  13. Install the water outlet tube. Refer to Water Outlet Tube Replacement in Engine Cooling.
  14. Install the glow plug relay bracket. Refer to Glow Plug Relay Replacement in Engine Controls - 6.6L.
  15. Install the fuel/filter heater element housing. Refer to Fuel Filter Assembly Replacement in Engine Controls - 6.6L.
  16. Install the auxiliary generator, if equipped. Refer to Auxiliary Generator Replacement in Engine Electrical.

    17. Object Number: 674616 Size: SH
  17. Connect the fuel hoses. Push in until locked.
  18. Install the nut retaining the fuel hose bracket to the valve rocker arm cover.

    19. Tighten
    Tighten the fuel hose bracket nut to 21 N·m (15 lb ft).

  19. Position the generator positive cable.
  20. Install the generator positive cable in the clip on the engine front cover.
  21. Install the generator positive cable and the retaining nut to the generator.

    22. Tighten
    Tighten the generator positive cable nut to 9 N·m (80 lb in).


    Object Number: 664853 Size: SH
  22. Install the charged air cooler inlet duct to turbocharger charge air cooler outlet.
  23. Align the marks on the hose and the intake manifold duct.

    24. Tighten
    Tighten the charge air cooler clamps to 6 N·m (53 lb in).

  24. Check for external fuel leaks. Refer to Fuel System Diagnosis in Engine Controls - 6.6L.
  25. Install air cleaner layer. Refer to Air Cleaner Replacement in Engine Controls - 6.6L.
  26. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim.
  27. Fill the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  28. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.