Chevrolet Silverado / GMC Sierra. Service manual — part 163

Be careful not to scuff the combustion chambers.

5. Inspect the cylinder head for the following:

Damage to the gasket surfaces

Damage to the threaded bolt holes

Burnt or eroded areas in the combustion chamber

Cracks in the exhaust ports and combustion chambers

External cracks in the water chamber

Restrictions in the intake or exhaust passages

Restrictions in the cooling system passages

Rusted, damaged, or leaking core plugs

Fig. 544: Inspecting Cylinder Head For Warpage
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

6. Measure the cylinder head for warpage with a straight edge and feeler gage.

A cylinder head block deck with warpage in excess of 0.10 mm (0.004 in) within a
152.4 mm (6.0 in) area must be repaired or replaced.

A cylinder head exhaust manifold deck with warpage in excess of 0.05 mm (0.002 in)
within a 152.4 mm (6.0 in) area must be repaired or replaced.

A cylinder head intake manifold deck with warpage in excess of 0.10 mm (0.004 in)
within a 152.4 mm (6.0 in) area must be repaired or replaced.

Fig. 545: Measuring Valve Spring Tension

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

Courtesy of GENERAL MOTORS CORP.

7. Use the J 9666 in order to measure the valve spring. See Special Tools.

Replace the valve spring if the valve spring tension is less than 338 N (76 lb) at 43.2 mm
(1.70 in).

Fig. 546: Inspecting Valve Spring For Squareness
Courtesy of GENERAL MOTORS CORP.

8. Inspect the valve springs for squareness.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

Fig. 547: Inspecting For Excessive Valve Stem To Guide Clearance
Courtesy of GENERAL MOTORS CORP.

9. Valve stems (1) with excessive valve guide (2) clearance must be repaired or the cylinder

head replaced.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado