Removal Procedure
Tools Required
Important: The timing chain housing to cylinder block and the camshaft housing
gaskets can be replaced without removing the timing chain housing from the
vehicle.
Removal of the timing chain housing is only required when additional
service is being performed on the timing chain housing.
- Disconnect the negative battery cable. Refer to
Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing
any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to
the vehicle or its components.
in General Information.
- Remove the engine front cover. Refer to
Engine Front Cover Replacement
.
- Raise and support the vehicle. Refer to SECTION 0A.
- Disconnect the heater hose from the thermostat housing in order
to drain the cylinder block completely.
Important: The timing chain must be marked prior to removal. If the chain is installed
with the wear pattern in the opposite direction, noise and increased wear
may occur.
- Remove the timing chain tensioner. Refer to
Camshaft Timing Chain, Sprocket, and Tensioner Replacement
.
- Remove the timing chain. Refer to
Camshaft Timing Chain, Sprocket, and Tensioner Replacement
.
- Remove the coolant pump assembly to the timing chain housing nuts.
Refer to Coolant Pump Replacement in Engine Cooling.
- Remove the timing chain housing to the block fasteners.
- Remove the four oil pan to front cover bolts.
- Remove the lowest front cover retaining stud from the timing chain
housing.
This stud will catch on the body if it is not removed.
- Lower the vehicle.
- Remove the camshaft sprocket retaining bolts and the washers while holding
the sprockets with the J 38122-A
.
- Remove the camshaft sprockets.
The camshaft sprockets are identical and interchangeable.
- Remove the chain housing to the camshaft housing bolts.
- Remove the timing chain housing and the gaskets.
It may be necessary to raise the engine slightly using the J 28467-360
.
- Inspect the oil pan gasket silicone bead for the following conditions:
• | Separation from the aluminum carrier |
- If any of the conditions exist, replace the pan gasket.
Important: Use only enough sealant to restore the silicone bead to its original
dimension. Excess application of sealant may cause part misalignment and oil
leaks.
- Inspect the silicone bead across the top of the aluminum carrier at
the oil pan, in the cylinder block, and to the timing chain housing three
way joint. Repair a damaged bead using the Silicone Rubber Sealant GM P/N 12345739
or the equivalent.
Installation Procedure
- Prior to installing the timing chain housing, ensure that the
alignment dowel pins are in the cylinder block and the timing chain housing.
The dowel pins ensure proper chain housing and the front cover location for
correct front oil seal-to-crankshaft alignment.
- Install the timing chain housing and the new gaskets. Gasket sealer
is unnecessary.
Important: Hand tighten all chain housing bolts before tightening to specifications.
- Install the chain housing to the camshaft housing bolts and hand tighten.
- Raise and support the vehicle. Refer to SECTION 0A.
- Install the timing chain housing block fasteners and hand tighten.
- Install the oil pan to the timing chain housing bolts and hand
tighten.
- Tighten the timing chain housing block fasteners.
Tighten
• | (1) (M8 X 1.25 X 25) 26 N·m (19 lb ft). |
• | (2) (M8 X 1.55 X 55) 50 N·m (37 lb ft). |
• | (3) (M10 X 1.25 X 35) 29 N·m (21 lb ft). |
- Tighten the oil pan to the timing chain housing bolts.
Tighten
• | (1) (M8 X 1.25 X 80) 24 N·m (18 lb ft). |
• | (2) (M8 X 1.24 X 22) 24 N·m (18 lb in). |
• | (3) (M6 X 1.00 X 25) 12 N·m (106 lb ft). |
- Install the lowest front cover retaining stud into the timing chain
housing.
- Install the coolant pump to the timing chain housing and the timing
chain housing nuts.
Tighten
Tighten the timing chain housing nuts to 26 N·m (19 lb ft).
- Lower the vehicle.
- Tighten the timing chain housing to the camshaft housing bolts.
Tighten
• | (1) (M8 X 1.25 X 25) 26 N·m (19 lb ft). |
• | (2) (M10 X 1.55 X 55) 50 N·m (37 lb ft). |
• | (3) (M8 X 1.25 X 35) 29 N·m (21 lb ft). |
- Install the camshaft sprockets.
The camshaft sprockets are identical and interchangeable.
- Install the camshaft sprocket bolts and the washers.
- Tighten the camshaft sprocket bolts and the washers while holding
the sprocket with the J 38122-A
.
Tighten
Tighten the camshaft sprocket bolts to 70 N·m (52 lb ft).
- Use the Adhesive/Sealant Compound GM P/N 12345493
or the equivalent on the camshaft sprocket bolts.
- Clean the old sealant off of the bolt with a wire brush.
- Clean the threaded hole in the camshaft with a round nylon brush.
- Clean the threaded hole in the camshaft with a round nylon brush.
Important: The side of the timing chain that was marked during the removal must
be showing when the chain is installed.
- Install the timing chain and the tensioner. Refer to
Camshaft Timing Chain, Sprocket, and Tensioner Replacement
.
- Install the front cover and the gaskets. Refer to
Engine Front Cover Replacement
.
- Connect the negative battery cable.