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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 271 (Engine Mechanical - 4.8L, 5.3L, 6.0L Or 6.2L (4 Of 5)) >> Off-Vehicle Repair Instructions (2 Of 3) >> Cylinder Head Cleaning and Inspection >> Cleaning/Inspection Procedure

Cleaning/Inspection Procedure

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    Fig 1: Cleaning Carbon Using J 8089
    GM4957Courtesy of GENERAL MOTORS CORP.
    CAUTION: Refer to Safety Glasses Caution .
    IMPORTANT:
    • When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).
    • Be careful not to scuff the chamber.
  1. Clean the following components:
    • Use the J 8089  in order to remove the carbon from the combustion chambers. See Special Tools .
    • Gasket surfaces

      Refer to Replacing Engine Gaskets .

    • Valve stems and heads on a buffing wheel
    • Bolt hole threads

      Remove all dirt, debris, or threadlocking material from the bolt holes.

  2. Inspect the cylinder head for the following conditions:
    1. Cracks in the exhaust ports and combustion chambers
    2. External cracks in the water chambers
    3. Gasket surfaces for excessive scratches or gouging

      Refer to Replacing Engine Gaskets .

    4. Bolt hole threads for debris or damaged threads

      Refer to Thread Repair  or Thread Repair Specifications .

    3. Fig 2: Inspecting Cylinder Head For Warpage
    GM1552456Courtesy of GENERAL MOTORS CORP.
  3. Inspect the cylinder head for warpage. Refer to Engine Mechanical Specifications (RPO LY2 VIN C) or Engine Mechanical Specifications (RPO LMG VIN 0) or Engine Mechanical Specifications (RPO LY5 VIN J) or Engine Mechanical Specifications (RPO LC9 VIN 3) or Engine Mechanical Specifications (RPO L76 VIN Y) or Engine Mechanical Specifications (RPO LY6 VIN K) or Engine Mechanical Specifications (RPO L92 VIN 8) .
    4. Fig 3: Measuring Valve Spring Tension
    GM4960Courtesy of GENERAL MOTORS CORP.
  4. Use the J 9666  in order to measure the valve spring tension. See Special Tools . Refer to Engine Mechanical Specifications (RPO LY2 VIN C) or Engine Mechanical Specifications (RPO LMG VIN 0) or Engine Mechanical Specifications (RPO LY5 VIN J) or Engine Mechanical Specifications (RPO LC9 VIN 3) or Engine Mechanical Specifications (RPO L76 VIN Y) or Engine Mechanical Specifications (RPO LY6 VIN K) or Engine Mechanical Specifications (RPO L92 VIN 8) .
    5. Fig 4: Rivet-Type Plug
    GM2046466Courtesy of GENERAL MOTORS CORP.
  5. Inspect for a leaking plug (1). Second design applications use a rivet-type plug at the top rear coolant passage of each cylinder head. If service of a leaking plug is required, it is necessary to remove the cylinder head from the engine to properly remove the plug. Refer to Cylinder Head Disassemble .
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