Cylinder Head Installation - Hummer H1 Service Manual

____________________________________________________________________
®

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 gas-
kets. The head gasket is made with sealant on the gasket sur-
face. 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 sys-
tems.
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).
05745159
HEAD BOLT
CYLINDER HEAD
HEAD
GASKET
Figure 2-176: Cylinder Head and Gasket
Installation
Figure 2-177: Cylinder Head Bolt Tightening
Sequence
Engine 2-89
DOWELS