- 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 center lower intake manifold bolts (1, 2, 3, 4) in sequence to 20 N·m (15 lb ft).
- Tighten the visible corner lower intake manifold bolts (5, 8,) to 25 N·m (18 lb ft).
- Tighten the hidden corner lower intake manifold bolts (6, 7) to 25 N·m (18 lb ft).
- Inspect the heater inlet pipe and seal for damage and replace if necessary.
- Install the heater inlet pipe stud, if necessary.
- Install the heater inlet pipe.
- Install the heater inlet pipe nut.
- Inspect the fuel rail, fuel injectors, and fuel injector O-rings for damage and replace if necessary.
- Lubricate the fuel injector O-ring 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.
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.
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: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Tighten
Tighten
Tighten the heater inlet pipe stud to 35 N·m (26 lb ft).
Tighten
Tighten the heater inlet pipe nut to 25 N·m (18 lb ft).
Tighten
Tighten the fuel injector rail bolts to 10 N·m (89 lb in).
