Removal Procedure
- Partially drain the cooling system. Refer to
Cooling System Draining and Filling
in Engine Cooling.
- Remove
the front ignition wire harness at the upper intake manifold and at the spark plugs.
- Remove the thermostat bypass pipe. Refer
to
Thermostat Bypass Pipes Replacement
in
Engine Cooling.
- Disconnect the positive crankcase ventilation (PCV) vacuum hose.
Notice: Valve rocker arm cover
gasket and sealant must be carefully trimmed away from lower intake manifold gasket.
Failure to do so will damage the lower intake manifold gasket, causing a severe oil
leak.
- Remove the valve rocker cover bolts.
Important: When removing the valve rocker arm cover,
ensure the gasket stays in place attached to the cylinder head.
- Remove the valve rocker cover.
Bump the end of the valve rocker
cover with the palm of your hand or a soft rubber mallet if the cover adheres to
the cylinder head.
- Trim the valve cover gasket and sealant away from the
lower intake manifold gasket at the cylinder head to lower intake manifold joints (1).
- Remove the valve cover gasket.
- Clean the sealing surface on the cylinder head with degreaser.
- Clean the valve rocker arm cover. Refer to
Valve Rocker Arm Cover Cleaning and Inspection
.
Installation Procedure
Important: All gasket mating surfaces need to be free
of oil and foreign material. Use GM P/N 12346139 (Canadian P/N 10953463)
or equivalent, to clean surfaces.
Important: Apply sealant GM P/N 12378521
(Canadian P/N 88901148), or equivalent at the cylinder head to lower
intake manifold joint.
- Apply sealant at the cylinder head to lower intake manifold joints (1).
- Install
a new gasket to the valve rocker cover. Ensure that the gasket is properly seated
in the groove of the valve rocker arm cover.
- Install the valve rocker cover.
Notice: Refer to Fastener Notice in the Preface section.
- Install the valve rocker cover bolts.
Tighten
Tighten the bolts to 10 N·m (89 lb in).
- Connect the PCV valve vacuum line.
- Install the thermostat bypass pipe. Refer
to
Thermostat Bypass Pipes Replacement
in
Engine Cooling.
- Install the front ignition wire harness.
- Fill the cooling system. Refer to
Cooling System Draining and Filling
in
Engine Cooling.