Chevrolet Silverado / GMC Sierra. Service manual — part 581

Fig. 12: View Of Valve Stem Oil Seal & Valve Spring
Courtesy of GENERAL MOTORS CORP.

2. Remove the valve keys (1).

3. Remove the J 8062 from the cylinder head.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

4. Remove the valve spring upper seat (2).

5. Remove the valve spring (3).

6. Remove the valve (6).

7. Remove the valve stem seal (4) using J 38820 . See Special Tools .

8. Remove the valve spring lower seat (5).

CYLINDER HEAD CLEANING AND INSPECTION

Tools Required

J 9666 Valve Spring Tester

EN-47909 Injector Bore and Sleeve Cleaning Kit

Inspection

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Fig. 13: Measuring Cylinder Head For Warpage
Courtesy of GENERAL MOTORS CORP.

1. Clean the cylinder head of all foreign material. Do not use a motorized wire brush on any

gasket sealing surface.

2. Clean the threaded holes.

3. Clean the injector bores using EN-47909 .

4. Inspect the cylinder head for the following:

Damage to the gasket surfaces

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Damage to the threaded bolt holes

Cracks in the exhaust ports

External cracks in the water chamber

Cracks between the valve seats

Restrictions in the intake or exhaust passages

Restrictions in the cooling system passages

Rusted, damaged or leaking core plugs

5. Measure the cylinder head for warpage with a straight edge and a feeler gauge. A cylinder

head block deck with warpage in excess of 0.075 mm (0.0030 in) within a 516.5 mm (20.33
in) area must be replaced.

Fig. 14: Measuring Cylinder Head Exhaust Manifold Deck For Warpage
Courtesy of GENERAL MOTORS CORP.

6. Measure the cylinder head exhaust manifold deck for warpage. A cylinder head exhaust

manifold deck with warpage in excess of 0.1 mm (0.0039 in) within a 453 mm (17.83 in)
area must be replaced.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado