Intake Manifold: Service and Repair

Fig. 2 Upper Intake & Fuel Rail Removal:

1. Disconnect battery ground cable.
2. Drain cooling system.
3. Remove air cleaner assembly, including air flow duct from throttle body.
4. Remove all cables at throttle body, then disconnect brake vacuum pipe at upper intake manifold.
5. Remove cable bracket at upper intake manifold, then all necessary vacuum lines.
6. Remove EGR valve, throttle body and ignition wire plastic shield bolts from upper intake manifold.
7. Remove front and rear ignition coil nuts and bolts, then coil.
8. Remove upper intake attaching bolts, then upper intake manifold, Fig. 2.
9. Relieve fuel pressure as outlined under Powertrain Management/Fuel Delivery and Air Induction/Fuel Pressure Release, then remove fuel lines at fuel rail.
10. Remove serpentine drive belt, then alternator. Position alternator aside.
11. Remove power steering lines at alternator bracket, then power steering pump mounting bolts. Position pump aside.
12. Remove wiring from fuel injectors.
13. Remove bypass hose at water pump and cylinder head.
14. Remove PCV hose, then front valve cover.
15. Remove alternator brace and bracket, then rear valve cover.
16. Remove upper radiator hose, then all necessary wiring.
17. Remove coolant sensor, then fuel lines at bracket.
18. Remove throttle body heater hose, then heater pipe at intake.
19. Remove lower intake manifold attaching bolts, then lower intake manifold. Ensure washers are retained in their original positions on four center bolts.

Fig. 3 Intake Manifold Tightening Sequence:

20. Reverse procedure to install, noting the following:
a. Apply small drops (8 - 10 mm [0.31 - 0.39 in]) of RTV sealer, GM P/N 12346286 (in Canada, use GM P/N 10953476) or the equivalent to the four corners of the intake manifold to block joint (1).

b. Connect the small drops with a bead of RTV sealer that is between 8 - 10 mm (0.31 - 0.39 in) wide and 3.0 - 5.0 mm (0.12 - 0.20 in) thick (2).

c. Tighten lower intake manifold vertical bolts first, then tighten diagonal bolts Fig. 3.
Failure to tighten vertical bolts before diagonal bolts may cause an oil leak.

d. Tighten all bolts and nuts to specifications.