Intake Manifold Replacement - Lower
Intake Manifold Replacement-LowerRemoval Procedure
Important: This engine uses a sequential multiport fuel injection system. Injector wiring harness connectors must be connected to their appropriate fuel injector or exhaust emissions or engine performance may be seriously affected.
1. Remove the upper intake manifold.
2. Remove the right (rear) and left (front) valve rocker arm covers.
3. Disconnect the Engine Coolant Temperature (ECT) sensor electrical connector.
4. Remove the fuel injector rail with lines and position aside.
5. Remove the power steering pump from the front engine cover and reposition.
6. Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition.
7. Remove the lower intake manifold bolts.
8. Remove the lower intake manifold.
9. Remove rocker arms and push rods.
10. Remove the lower intake manifold gaskets and seals.
11. Clean all gasket and seal surfaces.
12. If replacing the lower intake manifold remove the ECT sensor.
13. If replacing the lower intake manifold remove the water outlet bolts.
14. Remove the water outlet.
15. If replacing the lower intake manifold remove the thermostat.
Installation Procedure
1. It removed, install the thermostat.
2. If removed, install the water outlet.
Notice: Refer to Fastener Notice in Service Precautions.
3. Install the water outlet bolts.
^ Tighten the water outlet bolts to 25 Nm (18 ft. lbs.).
4. If removed, install the ECT sensor.
^ Tighten the ECT sensor to 23 Nm (17 ft. lbs.).
5. Apply 8 - 12 mm (0.08 - 0.11 inch) bead of RTV Sealer, GM P/N 12345739 or equivalent, on each ridge where front and rear of the lower intake manifold contact the engine block (1).
6. Install the lower intake manifold gaskets.
7. Install rocker arms and pushrods.
8. Install the lower intake manifold.
9. Apply sealant, GM P/N 12345382 to the threads of the lower intake manifold bolts.
Notice: An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.
10. Install the vertical lower intake manifold bolts until snug.
11. Install the diagonal lower intake manifold bolts until snug.
12. Install NEW lower intake manifold bolts.
Tighten
A. Tighten the lower intake manifold bolts in sequence to 7 Nm (62 in. lbs) on the first pass.
B. Tighten the lower intake manifold bolts (1,2,3,4) in sequence to 13 Nm (115 in. lbs) on the final pass.
C. Tighten the lower intake manifold bolts (5,6,7,8) in sequence to 25 Nm (18 ft. lbs) on the final pass.
13. Connect the heater inlet pipe and heater hose to the lower intake manifold.
14. Install the power steering pump to the front engine cover.
15. Install the fuel injector rail.
16. Connect the ECT sensor electrical connector.
17. Install the upper intake manifold.
18. Install the valve rocker covers.