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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 994 (Engine Mechanical - 6.6L (LLY)) >> Repair Instructions >> On-Vehicle Repair Instructions >> Valve Clearance Adjustment

Valve Clearance Adjustment

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove the fan clutch. Refer to Fan Clutch Replacement in Engine Cooling.
  2. Remove the upper valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Upper Left  and Valve Rocker Arm Cover Replacement - Upper Right .
  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. Fig 1: View Of Crankshaft Balancer Mark Aligned With Engine Mark
    GM667477Courtesy of GENERAL MOTORS CORP.
    Fig 2: View Of Feeler Gauge Between Tip Of The Rocker Arm & Valve Bridge
    GM663897Courtesy of GENERAL MOTORS CORP.
  4. Loosen the valve adjusting screws.
  5. Insert a feeler gauge between the tip of the rocker arm and the valve bridge.
  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.
    NOTE: Refer to Fastener Notice in Cautions and Notices.
  7. Tighten the lock nut.

    Tighten:  Tighten nut to 22 N.m (16 lb ft).

    8. Fig 3: View Of Rocker Arm Intake & Exhaust Valves 1, 2, 3, 5, 6, 7 & 8
    GM663110Courtesy of GENERAL MOTORS CORP.
  8. Rotate the crankshaft one revolution in order to bring the number 1 cylinder to TDC of the exhaust stroke.
    9. Fig 4: View Of Crankshaft Balancer Mark Aligned With Engine Mark
    GM667477Courtesy of GENERAL MOTORS CORP.
  9. Loosen the valve adjusting screws.
  10. Insert a feeler gage between the tip of the rocker arm and the valve bridge.
    11. Fig 5: View Of Feeler Gauge Between Tip Of The Rocker Arm & Valve Bridge
    GM663897Courtesy of GENERAL MOTORS CORP.
  11. Adjust the valve clearance to 0.3 mm (0.0112 in). Refer to Valve Clearance Adjustment Specifications to determine which valves can be adjusted when the engine is at TDC.
    12. Fig 6: View Of Rocker Arm Intake & Exhaust Valves 2, 3, 4, 5, 6, 7 & 8
    GM660548Courtesy of GENERAL MOTORS CORP.
  12. Tighten the lock nut.

    Tighten:  Tighten nut to 22 N.m (16 lb ft).

  13. Install the upper valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Upper Left  and Valve Rocker Arm Cover Replacement - Upper Right .
  14. Install the fan clutch. Refer to Fan Clutch Replacement in Engine Cooling.
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