Cylinder Head Cleaning and Inspection

Tools Required

• J 8089  Carbon Removal Brush. See Special Tools .
• J 9666  Valve Spring Tester. See Special Tools .

Fig 1: Removing Carbon From Combustion Chambers
Courtesy of GENERAL MOTORS CORP.
IMPORTANT: When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).
1. Clean the following components:
   CAUTION: Refer to Safety Glasses Caution .
   IMPORTANT: Be careful not to scuff the chamber.
   • 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.

Fig 2: View Of Cylinder Head Components
Courtesy of GENERAL MOTORS CORP.
2. Inspect the following components:
   1. The cylinder head (218) for cracks in the exhaust ports and combustion chambers
   2. The cylinder head for external cracks in the water chambers
   3. The gasket surfaces for excessive scratches or gouging

      Refer to Replacing Engine Gaskets .

   4. The bolt hole threads for debris or damaged threads

      Refer to Thread Repair  or Thread Repair Specifications .

Fig 3: Inspecting Cylinder Head For Warpage
Courtesy of GENERAL MOTORS CORP.
3. Inspect the cylinder head for warpage. Refer to Engine Mechanical Specifications (LR4 VIN V) or Engine Mechanical Specifications (LM7 VIN T) or Engine Mechanical Specifications (LQ4 VIN U) .
Fig 4: Inspecting Valve Spring For Squareness
Courtesy of GENERAL MOTORS CORP.
4. Inspect the valve springs for squareness.
Fig 5: Measuring Valve Spring Tension
Courtesy of GENERAL MOTORS CORP.
5. Use the J 9666  in order to measure the valve spring tension. See Special Tools .

   Replace the spring if the spring tension is less than 310 N (70 lb) at 45.75 mm (1.80 in).