GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Mechanical - 6.6L (LB7) 🢒 Positive Crankcase Ventilation Valve Replacement

Removal Procedure
  1. Remove air cleaner layer. Refer to Air Cleaner Replacement in Engine Controls .

    2. Important: After removing the turbocharger air ducts and hoses, cover the turbocharger openings and the ducts with tape to prevent entry of objects.

  2. If removing the right side, remove the charged air cooler outlet duct from the air cleaner and the turbocharger.

    3. Object Number: 664851 Size: SH
  3. If removing the right side, loosen both charged air cooler outlet duct to intake hose clamps.

    4. Important: Do not use a screw driver or other tool to pry the hose loose. Loosen the hose by twisting.

  4. Remove the charged air cooler outlet duct to intake hose.

    5. Object Number: 664853 Size: SH
  5. If removing the left side, loosen the charged air cooler inlet duct to turbocharger clamp.

    6. Important: Do not use a screw driver or other tool to pry the hose loose. Loosen the hose by twisting.

  6. Remove the charged air cooler inlet duct to turbocharger cool air outlet hose from the turbocharger. The hose can stay on the pipe.

    7. Object Number: 663631 Size: SH
  7. Remove the screws retaining the PCV diaphragm cover to the valve rocker arm cover.
  8. Remove the diaphragm cover.
  9. Remove the diaphragm and the spring.
  10. Clean the diaphragm cover, spring, and screws.
  11. Inspect the diaphragm for cuts or damage.
  12. Discard the diaphragm if damage is found.

Installation Procedure

    Object Number: 663631 Size: SH
  1. Install the spring, diaphragm and cover to the valve rocker arm cover.

    2. 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.

  2. Install the PCV diaphragm cover screws.

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


    Object Number: 664853 Size: SH
  3. Install the charged air cooler inlet duct to turbocharger cool air outlet hose to the turbocharger.
  4. Position the clamp as shown for proper clearance.

    5. Tighten
    Tighten the clamp to 6 N·m (53 lb in).


    Object Number: 664851 Size: SH
  5. Install the charged air cooler outlet duct to intake hose.

    6. The hose is marked DUCT which connects to the charged air cooler outlet duct.

    The hose is marked ENG which connects to the intake manifold duct.

    Align the marks on the hose with the alignment marks on the pipe and duct.

  6. Position the clamps as shown for proper clearance.

    7. Tighten
    Tighten the clamps to 6 N·m (53 lb in).

  7. Install air cleaner layer. Refer to Air Cleaner Replacement in Engine Controls.