GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Mechanical - 6.6L 🢒 Valve Clearance Adjustment

    Object Number: 667477 Size: SH
  1. Remove the fan clutch. Refer to Fan Clutch Replacement .
  2. Remove the upper valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Upper Left Side and Valve Rocker Arm Cover Replacement - Upper Right Side .
  3. Rotate the crankshaft in order to bring the number 1 cylinder to top dead center (TDC) of the compression stroke. The number 1 cylinder is the front cylinder on the right bank. The mark on the crankshaft balancer should be aligned with the mark on the engine.

    4. Object Number: 663897 Size: SH
  4. Loosen the valve adjusting screws.
  5. Insert a feeler gage between the tip of the rocker arm and the valve lifter bridge.

    6. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 663110 Size: SH
  6. Adjust the valve lash to 0.3 mm (0.012 in). Refer to Valve Clearance Adjustment Specifications to determine which valves can be adjusted when the engine is at TDC.

    7. Tighten
    Tighten lock nut to 22 N·m (16 lb ft).


    Object Number: 667477 Size: SH
  7. Rotate the crankshaft one revolution in order to bring the number 1 cylinder to TDC of the exhaust stroke.

    8. Object Number: 663897 Size: SH
  8. Loosen the valve adjusting screws.
  9. Insert a feeler gage between the tip of the rocker arm and the valve lifter bridge.

    10. Object Number: 660548 Size: SH
  10. Adjust the valve clearance to 0.3 mm (0.012 in). Refer to Valve Clearance Adjustment Specifications to determine which valves can be adjusted when the engine is at TDC.

    11. Tighten
    Tighten lock nut to 22 N·m (16 lb ft).

  11. Install the upper valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Upper Left Side and Valve Rocker Arm Cover Replacement - Upper Right Side .
  12. Install the fan clutch. Refer to Fan Clutch Replacement .