Cylinder Head Cleaning and Inspection Off Vehicle

Warning: Refer to Safety Glasses Warning in the Preface section.





Note: Machining of the cylinder head for flatness is not recommended as this would increase the compression ratio of the engine. If the flatness or height measurements are not within the specifications, replace the cylinder head.

1. Clean the sealing surfaces.
2. Inspect the cylinder head gasket and mating surfaces for leaks, corrosion, and blowby.
3. Inspect the cylinder head for cracks.
4. Inspect the length and the width of the cylinder head using a feeler gage and a straight edge.
5. Check the sealing surfaces for damage. The cylinder head sealing surfaces must be flat within 0.050 mm (0.002 in) maximum.



6. Measure the height of the cylinder head from sealing surface to sealing surface. The cylinder head height should be 138.13-138.18 mm (5.438-5.440 in). If the cylinder head height is less than this value, replace the cylinder head.
7. Inspect all threaded holes for damage.
8. Inspect valve seats for excessive wear and burned spots.

Cylinder Head Cleaning and Inspection On Vehicle

Warning: Refer to Battery Disconnect Warning in the Preface section.




1. Disconnect the negative battery cable.
2. Remove the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement.
3. Locate the cylinder head casting (1) in the cylinder head between the spark plug holes (2).




Note: If the cylinder head casting plug is leaking coolant, it should have and sludge build up around the plug.

4. Inspect the area (3) around the cylinder head casting plug (1) for coolant leakage. Pressure test the cooling system if necessary.
5. If coolant leakage is identified, remove both cylinder head casting plugs.
6. Thoroughly clean the plugs and the cylinder head.
7. Apply Pipe Sealant with Teflon®, GM P/N 12346004, (Canadian P/N 10953480) to the plug threads.
8. Install the cylinder head casting plugs into the cylinder head

Tighten
Tighten the cylinder head casting plugs to 95 N·m (70 lb ft)

9. Install the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement
10. Connect the negative battery cable.