GM Service Manual Online
For 1990-2009 cars only

Tools Required

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

    Caution: Refer to Safety Glasses Caution in the Preface section.


    Object Number: 1950885  Size: SH

    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:
  2. • Use a commercially available rotary wire brush 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.
  3. Inspect the cylinder head for the following conditions:
  4. 2.1. Cracks in the exhaust ports and combustion chambers.
    2.2. External cracks in the water chambers.
    2.3. Gasket surfaces for above acceptable scratches or gouging.

    Refer to Replacing Engine Gaskets .

    2.4. Bolt hole threads for debris or damaged threads

    Refer to Thread Repair and Thread Repair Specifications .


    Object Number: 1950887  Size: SH
  5. Check the cylinder head deck and the inlet and exhaust manifold mating surfaces for distortion. Use a set of feeler gauges (1) and a straight edge (2). Check along the length (A), laterally (B) and diagonally (C).
  6. Check the flatness of the cylinder block and cylinder head deck surfaces. If the measurement is not within specification, the cylinder block must be replaced. machining is not recommended. Refer to Engine Mechanical Specifications .

  7. Object Number: 1950889  Size: SH
  8. Measure the overall height of the cylinder head (A) and ensure it is within the specified limit. Refer to Engine Mechanical Specifications .