GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 TrailBlazer - 2WD 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Valve Rocker Arm Cover Replacement - Left Side

Removal Procedure

    Object Number: 898326 Size: SH
  1. Remove the connector position assurance (CPA) lock.
  2. Disconnect the main electrical connector (5) to the ignition coil wire harness.
  3. Remove the harness clips.
  4. Reposition the engine harness, if necessary.
  5. Remove the spark plug wires from the ignition coils.
    6. • Twist each plug wire 1/2 turn.
    • Pull only on the boot in order to remove the wire from the ignition coil.

    Object Number: 824413 Size: SH
  6. If necessary, remove the ignition coil bracket studs from the rocker arm cover.
  7. If necessary, remove the ignition coils and bracket from the rocker arm cover.

    8. Object Number: 647793 Size: SH
  8. Remove the positive crankcase ventilation (PCV) hose from the rocker arm cover.

    9. Object Number: 260085 Size: SH
  9. Remove the valve rocker arm cover bolts.
  10. Remove the valve rocker arm cover.

    11. Object Number: 490696 Size: SH
  11. Remove the gasket (1) from the rocker cover.
  12. Discard the OLD gasket.

Installation Procedure

Important: 

   • All gasket surfaces should be free of oil an/or other foreign material during assembly.
   • DO NOT reuse the valve rocker arm cover gasket.
   • The valve rocker arm cover bolt grommets may be reused.
   • If the PCV valve grommet has been removed from the rocker cover, install a NEW grommet during assembly.


    Object Number: 490696 Size: SH
  1. Install a NEW rocker cover gasket (1) into the groove of the valve rocker arm cover.

    2. Object Number: 260085 Size: SH
  2. Install the valve rocker arm cover onto the cylinder head.
  3. Install new rocker arm cover grommets, if necessary.

    4. 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.

  4. Install the rocker arm cover bolts.

    5. Tighten
    Tighten the bolts to 12 N·m (106 lb in).


    Object Number: 647793 Size: SH
  5. Install the PCV hose to the rocker arm cover.

    6. Object Number: 824413 Size: SH
  6. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the bracket bolts.
  7. If necessary, install the ignition coils and bracket to the rocker arm cover.
  8. If necessary, install the ignition coil bracket studs to the rocker arm cover.

    9. Tighten
    Tighten the studs to 12 N·m (106 lb in).


    Object Number: 898326 Size: SH
  9. Install the spark plug wires to the ignition coils.
  10. Position the engine harness, if necessary.
  11. Install the harness clips.
  12. Connect the main electrical connector (5) to the ignition coil wire harness.
  13. Install the CPA lock.