Intake Manifold Replacement - Lower

Intake Manifold Replacement (Lower)

Removal Procedure

Important: This engine uses a sequential multiport fuel injection system. Injector wiring harness connectors must be connected to their appropriate fuel injector or exhaust emissions and engine performance may be seriously affected.

1. Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure.
2. Remove the upper intake manifold. Refer to Intake Manifold Replacement (Upper).
3. Disconnect the radiator inlet hose from the engine. Refer to Radiator Hose Replacement - Inlet in Cooling System.





4. Disconnect the thermostat bypass hose from the thermostat bypass pipe and lower intake manifold pipe.
5. Remove the thermostat bypass pipe.
6. Remove the left (front) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Left).
7. Remove the generator. Refer to Generator Replacement.
8. Remove the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Right).





9. Disconnect the engine coolant temperature (ECT) wiring harness.





10. Disconnect and remove the fuel injector and manifold air pressure (MAP) wiring harness.





11. Remove the fuel pipe clip bolt.





12. Remove the fuel pipe clip.





13. Disconnect the fuel feed pipe from the fuel injector rail. Refer to Fuel Hose/Pipes Replacement (Engine Compartment) in Powertrain Management.





14. Disconnect the fuel return pipe from the fuel injector rail. Refer to Fuel Hose/Pipes Replacement (Engine Compartment) in Powertrain Management.





15. Remove the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Powertrain Management.
16. Remove the power steering pump from the front engine cover and reposition. Refer to Power Steering Pump Replacement in Steering and Suspension.





17. Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition. Refer to Heater Pipe Replacement - Inlet in Heating and Air Conditioning.





18. Remove the lower intake manifold bolts.
19. Remove the lower intake manifold.
20. Remove the valve rocker arms and the push rods. Refer to Valve Rocker Arm and Push Rod Replacement.





21. Remove the lower intake manifold gaskets and seals.
22. Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
23. Clean the gasket and seal surfaces on the lower intake manifold with degreaser.
24. Remove all the loose RTV sealer.





25. If replacing the lower intake manifold remove the engine coolant temperature (ECT) sensor.





26. If replacing the lower intake manifold remove the water outlet bolts.
27. Remove the water outlet.





28. If replacing the lower intake manifold remove the thermostat.

Installation Procedure





1. If removed, install the thermostat.





2. If removed, install the water outlet.

Notice: Refer to Fastener Notice in Service Precautions.

3. Install the water outlet bolts.

Tighten
Tighten the water outlet bolts to 25 N.m (18 lb ft).





4. If removed, install the engine coolant temperature (ECT) sensor.





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.

5. Install the lower intake manifold gaskets.
6. 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 89022195) or equivalent to the 4 corners of intake manifold to block joint (1).
7. 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).
8. Install the push rods and the valve rocker arms. Refer to Valve Rocker Arm and Push Rod Replacement.
9. Install the lower intake manifold.





Important: All lower intake manifold bolts need to be cleaned and free of any foreign material, only new bolts are to be used.

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

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

10. Install NEW lower intake manifold bolts.

Tighten
1. Tighten the lower intake manifold bolts in sequence to 7 N.m (62 lb in) on the first pass.
2. Tighten the lower intake manifold bolts (1,2,3,4) in sequence to 13 N.m (115 lb in) on the final pass.
3. Tighten the lower intake manifold bolts (5,6,7,8) in sequence to 25 Nm (18 lb ft) on the final pass.





11. Install the heater inlet pipe.
12. Install the heater inlet pipe nut.

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

13. Install the power steering pump to the front engine cover. Refer to Power Steering Pump Replacement in Steering and Suspension.
13.1. Install the fuel injector O-rings using GM P/N 12345616 (Canadian P/N 993182) or equivalent.
13.2. Install the injector nozzles into the lower intake manifold injector bores.
13.3. Press on the injector rail using the palms of both hands until the injectors are fully seated.
14. Install the fuel injector bolts.

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





15. Connect the fuel return pipe to the fuel injector rail. Refer to Fuel Hose/Pipes Replacement (Engine Compartment) in Powertrain Management.





16. Connect the fuel feed pipe to the fuel injector rail. Refer to Fuel Hose/Pipes Replacement (Engine Compartment) in Powertrain Management.





17. Install the fuel feed and return pipe retaining clip.
18. Install the fuel feed and return pipe retaing clip bolt.

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





19. Connect the thermostat bypass hose to the thermostat bypass pipe and lower intake manifold pipe.
20. Connect the radiator inlet hose to the engine. Refer to Radiator Hose Replacement - Inlet in Cooling System.





21. Install and connect the fuel injector and manifold air pressure (MAP) wiring harness.





22. Connect the engine coolant temperature (ECT) wiring harness.
23. Install the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Right).
24. Install the generator. Refer to Generator Replacement.
25. Install the left (front) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Left).
26. Install the upper intake manifold. Refer to Intake Manifold Replacement (Upper).
27. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure.