Intake Manifold Installation - Lower: Notes

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.

1. Install the lower intake manifold gaskets.
   NOTE: When replacing lower intake manifold gasket, a revised intake manifold gasket has been introduced by manufacturer. This new design gasket helps resolve issues related to intake manifold oil/coolant leaks. The gasket requires a revised torque specification and procedure in addition to the use of NEW revised intake manifold bolts. Please review TSB ENGINE OIL OR COOLANT LEAK (INSTALL NEW INTAKE MANIFOLD GASKET) for complete information.
2. With gaskets in place apply a small drop 8-10 mm (0.31-0.39 in) of RTV sealer GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the 4 corners of the intake manifold to block joint (1).
3. Connect the 2 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).
4. Install the lower intake manifold.
   Fig 1: Installing Lower Intake Manifold

   Courtesy of GENERAL MOTORS CORP.
   NOTE: 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.

   Important:  All lower intake manifold bolts need to be cleaned, free of any foreign material, and reused only if new bolts are unavailable. Use GM P/N 12345382 (Canadian P/N 10953489) or equivalent and apply to the old intake manifold bolt threads.

   Important:  Manufacturer recommends the center bolts be fully torqued before the diagonal bolts to assure proper seal ability.

   Fig 2: Identifying Lower Intake Manifold Bolts Tightening Sequence

   Courtesy of GENERAL MOTORS CORP.

   Important:  Lower intake manifold bolts in location 6 and 7 should be torqued to specification using a crows foot type tool.

5. Install the lower intake manifold bolts.

   Tighten 

   1. 5.1. Tighten the lower intake manifold center bolts in sequence to 7 N.m (62 lb in) on the first pass.
   2. 5.2. Tighten the lower intake manifold center bolts in sequence to 13 N.m (115 lb in) on the final pass.
   3. 5.3. Tighten the lower intake manifold diagonal bolts in sequence to 13 N.m (115 lb in) on the first pass.
   4. 5.4. Tighten the lower intake manifold diagonal bolt in sequence to 25 N.m (18 lb ft) on the final pass.
6. Install the heater inlet pipe.
7. Install the heater inlet pipe nut.

   Tighten  Tighten the heater inlet pipe nut to 25 N.m (18 lb ft).

   Fig 3: Installing Heater Inlet Pipe

   Courtesy of GENERAL MOTORS CORP.

   Important:  Do not press on the fuel pressure regulator valve when installing the fuel injector rail assembly.

8. Install the fuel injector rail assembly.
   1. 8.1. Install the fuel injector O-rings using GM P/N 12345616, (Canadian P/N 993182) or equivalent
   2. 8.2. Install the injector nozzles into the lower intake manifold injector bores.
   3. 8.3. Press on the injector rail using the palms of both hands until the injectors are fully seated.
9. Install the fuel injector rail bolts.

   Tighten  Tighten the fuel injector rail bolts to 10 N.m (89 lb in).

   Fig 4: Installing Fuel Injector Rail Assembly

   Courtesy of GENERAL MOTORS CORP.
10. Install the fuel feed and return pipe retaining clip.
11. Install the fuel feed and return pipe retaining clip bolt.

    Tighten 

    Tighten the fuel feed and return pipe retaining clip bolt to 8 N.m (71 lb in).

    Fig 5: Installing Fuel Feed And Return Pipe Retaining Clip

    Courtesy of GENERAL MOTORS CORP.