Tools Required

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

J 8089 Carbon Removal Brush
J 9666 Valve Spring Tester

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

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.
- Gasket surfaces
  Refer to Replacing Engine Gaskets .
  
  Fig 1: Removing Carbon Using J 8089
  Courtesy of GENERAL MOTORS CORP.
- Valve stems and heads on a buffing wheel
- Bolt hole threads
  Remove all dirt, debris, or threadlocking material from the bolt holes.
Inspect the following:
1. 2.1. Worn or loose valve seats (8 or 11)
2. 2.2. The cylinder head for cracks in the exhaust ports and combustion chambers
3. 2.3. The cylinder head for external cracks in the water chambers
4. 2.4. The gasket surfaces for excessive scratches or gouging
  Refer to Replacing Engine Gaskets .
5. 2.5. The bolt hole threads for debris or damaged threads
  Refer to Thread Repair or Thread Repair Specifications .
  
  Fig 2: Inspecting Cylinder Head Components
  Courtesy of GENERAL MOTORS CORP.
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 (L59 VIN Z) or Engine Mechanical Specifications (LQ4 VIN U) or Engine Mechanical Specifications (LQ9 VIN N) .

Fig 3: Inspecting Cylinder Head For Warpage
Courtesy of GENERAL MOTORS CORP.
Inspect the valve springs for squareness.

Fig 4: Inspecting Valve Springs For Squareness
Courtesy of GENERAL MOTORS CORP.
Use the J 9666 in order to measure the valve spring tension.
Replace the spring if the spring tension is less than 310 N (70 lb) at 45.75 mm (1.80 in).

Fig 5: Measuring Valve Spring Tension Using J 9666
Courtesy of GENERAL MOTORS CORP.