Chevrolet Silverado / GMC Sierra. 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