- With gaskets and seals in place apply a small drop 8-10 mm (0.31-0.39 in) of room temperature vulcanizing (RTV) sealer GM P/N 12378521 (Canadian P/N 88901148) or equivalent to the 4 corners of the intake manifold to block joints (1).
- Install the lower intake manifold.
- Apply sealer GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the lower intake manifold bolt threads.
- Install the new lower intake manifold bolts if applicable, in sequence.
- Tighten the lower intake manifold bolts in sequence to 7 N·m (62 lb in) on the first pass.
- Tighten the lower intake manifold bolts (1, 2, 3, 4) in sequence to 13 N·m (115 lb in) on the final pass.
- Tighten the lower intake manifold bolts (5, 6, 7, 8) in sequence to 25 N·m (18 lb ft) on the final pass.
- Inspect the fuel rail, and fuel injectors for damage and replace if necessary.
- Install NEW lower fuel injector O-rings.
- Lubricate the fuel injector O-rings using GM P/N 12345616 (Canadian P/N 993182) or equivalent.
- Install the injector nozzles into the lower intake manifold injector bores.
- Press on the injector rail using the palms of both hands until the injectors are fully seated.
- Install the fuel injector rail bolts.
- Connect the coolant temperature sensor (1).
- Connect the camshaft position (CMP) sensor (2).
- Connect the LOMA connector.
- Install the LOMA connector bolts.
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: NEVER install the lower intake manifold with the fuel injection wiring harness and lifter oil manifold assembly (LOMA) connector attached. Failure to do so may cause damage to the LOMA and LOMA wiring connector. To ensure proper lower intake manifold orientation during installation, make sure the intake port marked 1 faces the front of the engine.
Notice: Maximum gasket performance is achieved when using new fasteners, which contain a thread-locking patch. If the fasteners are not replaced, a thread locking chemical must be applied to the fastener threads. Failure to replace the fasteners or apply a thread-locking chemical MAY reduce gasket sealing capability.
Notice: Failure to tighten vertical bolts before the diagonal bolts may cause an oil leak.
Notice: Refer to Fastener Notice in the Preface section.
Tighten
Important: To ensure proper fuel rail orientation during installation, make sure the fuel feed pipe faces the rear of the engine.
Tighten
Tighten the fuel injector rail bolts to 10 N·m (89 lb in).
Tighten
Tighten the LOMA connector bolts to 10 N·m (89 lb in).
