Cylinder Head Cleaning and Inspection

Special Tools

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

For equivalent regional tools, refer to Special Tools .

Fig 1: Cleaning Carbon Using J 8089
Courtesy of GENERAL MOTORS COMPANY
WARNING:

Refer to Safety Glasses Warning .

NOTE:
• 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  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.

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 .

Fig 2: Inspecting Cylinder Head For Warpage
Courtesy of GENERAL MOTORS COMPANY
3. Inspect the cylinder head for warpage. Refer to Engine Mechanical Specifications (RPO LMG VIN 0) , Engine Mechanical Specifications (RPO L9H) , Engine Mechanical Specifications (RPO L94 VIN F) , Engine Mechanical Specifications (RPO L96 VIN G) , Engine Mechanical Specifications (RPO LC9 VIN 7) .
Fig 3: Measuring Valve Spring Tension
Courtesy of GENERAL MOTORS COMPANY
4. Use the J 9666  tester in order to measure the valve spring tension. Refer to Engine Mechanical Specifications (RPO LMG VIN 0) , Engine Mechanical Specifications (RPO L9H) , Engine Mechanical Specifications (RPO L94 VIN F) , Engine Mechanical Specifications (RPO L96 VIN G) , Engine Mechanical Specifications (RPO LC9 VIN 7) .
Fig 4: Rivet-Type Plug
Courtesy of GENERAL MOTORS COMPANY
5. Inspect for a leaking plug (1) 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 .