Cylinder Head Cleaning and Inspection

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required

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 in Cautions and Notices.

Important: Be careful not to scuff the chamber.

Fig 1: Removing Carbon From Combustion Chambers Using J 8089
Courtesy of GENERAL MOTORS CORP.
- 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.
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 For Damage
Courtesy of GENERAL MOTORS CORP.
Inspect the cylinder head for warpage. Refer to Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V) or Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T) or Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z) or Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U) or Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N) .

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

Fig 4: Inspecting Valve Springs For Damage
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.