Duramax LLY – CYLINDER HEAD INSTALLATION

Important:
• Make sure that the block and head gasket surfaces are clean.
• The head gasket material is soft. Handle the gasket with care and make sure the gasket surface is not creased or dented.

CAUTION: Do not apply any type of sealant to the head gaskets. The head gasket is made with sealant on the gasket surface. Additional sealer may cause leakage and engine damage.

1. Place each head gasket on block deck and dowels (Figure 2-176).
2. Carefully position each cylinder head on gasket and on dowels (Figure 2-176).

CAUTION: Follow torque sequence for head bolts. This is necessary for correct compression of head gasket. Failure to do so will cause leaks.

NOTE: Use the correct fastener in the correct location. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Install cylinder head bolts as follows:
a. Apply Loctite 592 pipe thread sealant to bolt threads and under bolt heads.
b. Tighten bolts in sequence (Figure 2-177), to 20 lb-ft (25 N•m) torque.
c. Repeat bolt tightening sequence to a torque of 55 lb-ft (75 N•m).
d. Retighten bolts in sequence to 55 lb-ft (75 N•m).
e. Tighten bolts an additional 90-100 degrees (1/4 plus turn).

 

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