GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 8089 Carbon Removing Brush
    • J 9666 Valve Spring Tester

    Object Number: 4957  Size: SH

    Caution: Wear safety glasses in order to avoid eye damage.

    Important: When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).

  1. Clean the following components:
  2.    Important: Be careful not to scuff the chamber.

    • Use the J 8089 in order to remove the carbon from the combustion chambers.
    • 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.

    Object Number: 822537  Size: MH
  3. Inspect the following:
  4. 2.1. The cylinder head (1) for cracks in the exhaust ports and combustion chambers
    2.2. The cylinder head for external cracks in the water chambers
    2.3. The gasket surfaces for excessive scratches or gouging

    Refer to Replacing Engine Gaskets .

    2.4. The bolt hole threads for debris or damaged threads

    Refer to Thread Repair or Thread Repair Specifications .


    Object Number: 64318  Size: SH
  5. Inspect the cylinder head for warpage.

  6. Object Number: 40075  Size: SH
  7. Inspect the valve springs for squareness.

  8. Object Number: 4960  Size: SH
  9. Use the J 9666 in order to measure the valve spring tension.
  10. • Replace the LS1 spring if the spring tension is less than 310 N (70 lb) at 45.75 mm (1.80 in).
    • Replace the LS6 spring if the spring tension is less than 400 N (90 lb) at 45.75 mm (1.80 in).