Intake Manifold Installation - Lower

WARNING: This page is about a different car, the 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: When replacing 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.

Apply sealer GM P/N United States 12378479, GM P/N Canada 10953472 or the equivalent at the engine block-to-lower intake manifold mating surface.
Ensure that the bead meets the following conditions:
- 2.0-3.0 mm (0.08-0.12 in) wide
- 3.0-5.0 mm (0.12-0.20 in) thick
Install the lower intake manifold.

Fig 1: Lower Intake Manifold
Courtesy of GENERAL MOTORS CORP.

NOTE: Failure to tighten vertical bolts before the diagonal bolts may cause an oil leak.
Apply sealer GM P/N United States 12345382, GM P/N Canada 10953489 or the equivalent to the lower intake manifold bolt threads if reusing old bolts.
Install the lower intake manifold bolts.
Tighten: See TSB For Revised Lower Intake Torque

Fig 2: Lower Intake Manifold Bolt Tightening Sequence
Courtesy of GENERAL MOTORS CORP.
Install the heater inlet pipe.
Install the heater inlet pipe nut.
Tighten:

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

Fig 3: Heater Inlet Pipe And Nut
Courtesy of GENERAL MOTORS CORP.

NOTE: Do not press on the fuel pressure regulator valve when installing the fuel injector rail assembly.
Install the fuel injector rail assembly.
1. 7.1. Install the fuel injector O-rings using GM P/N United States 12345616, GM P/N Canada 993182 or the equivalent.
2. 7.2. Install the injector nozzles into the lower intake manifold injector bores.
3. 7.3. Press on the injector rail using the palms of both hands until the injectors are fully seated.
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.
Install the fuel feed and return pipe retaining clip.
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: Fuel Feed And Return Pipe
Courtesy of GENERAL MOTORS CORP.