Chevrolet Silverado / GMC Sierra. Manual - part 473
1. Install the cylinder head gasket of the correct grade. Refer to Cylinder Head Gasket
Selection Specifications .
2. Install the cylinder head.
Fig. 206: Cylinder Head Bolt Installation Sequence
Courtesy of GENERAL MOTORS CORP.
NOTE:
The left and right cylinder head gaskets are not
interchangeable. Improper placement of the cylinder head
gasket will block coolant and oil passages. Blocked coolant
and oil passages will cause severe engine damage.
NOTE:
This component uses bolts with a preapplied molybdenum
disulfide coating for thread lubrication. Do not remove the
coating or use any additional lubricant. Improperly lubricated
threads will adversely affect the bolt torque and clamp load.
Improper bolt torque and clamp load can lead to engine
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
3. Install the NEW M12 cylinder head bolts.
4. Reuse the M8 cylinder head bolts.
5. Tighten the cylinder head bolts in the following steps using the sequence shown:
Tighten:
1. Tighten the M12 bolts a first pass to 50 N.m (37 lb ft).
2. Tighten the M12 bolts a second pass to 80 N.m (59 lb ft)
3. Tighten the M12 bolts a third pass to 60 degrees, using J 45059 .
4. Tighten the M12 bolts a final pass to 60 degrees, using J 45059 .
5. Tighten the M8 bolts to 25 N.m (18 lb ft).
6. Install the valve rocker arm shaft, pushrods, and valve bridges. Refer to Valve Rocker
Arm, Shaft, and Push Rod Replacement.
7. Install the glow plugs. Refer to Glow Plug Replacement - Bank 1 .
8. Install the right exhaust manifold. Refer to Exhaust Manifold Replacement - Right Side
(6.6L) .
9. Install the right intake manifold. Refer to Intake Manifold Replacement - Right Side.
10. Install the thermostat housing crossover. Refer to Thermostat Housing Crossover
Replacement (LMM) .
11. Road test the vehicle for normal operation.
12. Inspect for coolant, oil, or exhaust leaks.
VALVE STEM OIL SEAL AND VALVE SPRING REPLACEMENT
Tools Required
J 26999 Compression Gage. See Special Tools .
J 26999-20 Compression Gage Adapter
J 44646 Valve Spring Compressor. See Special Tools .
J 44640 Valve Stem Seal Installer. See Special Tools .
Removal Procedure
damage.
NOTE:
Refer to Fastener Notice .
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Fig. 207: View Of J 26999-20 & J 26999
Courtesy of GENERAL MOTORS CORP.
1. Remove the upper and lower fan shroud. Refer to Engine Coolant Fan Lower Shroud
Replacement (Mechanical) and Engine Coolant Fan Upper Shroud Replacement
(Mechanical) or Engine Coolant Fan Upper Shroud Replacement (Automatic
Transmission - Diesel) .
2. Remove the valve rocker arm shaft, valve bridges, and pushrods for the cylinder head being
serviced. Refer to Valve Rocker Arm, Shaft, and Push Rod Replacement.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
3. Remove the glow plug for the cylinder requiring service. Refer to Glow Plug Replacement
- Bank 1 or Glow Plug Replacement - Bank 2 .
4. In order to apply shop air to the cylinders use the following procedures to modify J 26999-
20 (1) and J 26999 (2):. See Special Tools .
1. Remove the valve core from J 26999-20 to allow air to flow.
2. Remove the quick connect fitting from J 26999 . See Special Tools .
3. Adapt the quick connect fitting in order to use for shop air.
4. Connect the quick connect fitting to J 26999-20 .
5. Install J 26999-20 into the glow plug hole for the cylinder being serviced.
6. Apply compressed air to hold the valves in place. If the compressed air is released, the
valves can drop into the cylinder.
IMPORTANT: Rotate the cylinder to be serviced to the bottom of the stroke.
This is to ensure that the engine does not rotate when the
compressed air is applied to the cylinder being serviced.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado