Intake Manifold Replacement Upper

Important: This engine uses a sequential multiport fuel injection system. Connect the injector wiring harness connectors 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 Disconnection and Connection in Engine Electrical.
2. Carefully disconnect the vacuum hose connection from the throttle body air inlet duct.
3. Disconnect the wiring harness connection from the intake air temperature (IAT) sensor in the throttle body air inlet duct. Refer to Intake Air Temperature Sensor Replacement in Engine Controls - 3.4L.
4. Carefully disconnect the throttle body air inlet duct.
5. Drain the engine coolant from the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
6. Remove the accelerator control and cruise control cables with bracket from the throttle body. Refer to Accelerator Control Cable Bracket Replacement in Engine Controls - 3.4L.
7. Disconnect the wiring harness connectors from the throttle body:

•	Throttle position (TP) sensor

•	Idle air control (IAC) valve

8. Disconnect the wiring harness attachment clips.

•	Camshaft position (CMP) sensor wiring harness

•	Left spark plug wire harness

9. Disconnect the thermostat bypass pipe coolant hoses from the throttle body.
10. Remove the rear generator brace. Refer to Generator Brace Replacement in Engine Electrical.



11. Remove the following components:

11.1.

The vacuum lines at the upper intake manifold

11.2.

The MAP sensor

11.3.

The EGR valve

11.4.

The spark plug wires

11.5.

The ignition control module

11.6.

The upper intake manifold

11.7.

The upper intake manifold gaskets

Refer to Intake Manifold Removal .

12. Remove the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 3.4L.
13. Clean the seal surfaces on the manifold with degreaser.

1. Install the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 3.4L.



2. Install the following components:

2.1.	The upper intake manifold gaskets

2.2.	The upper intake manifold

2.3.	The ignition control module

2.4.	The spark plug wires

2.5.	The EGR valve

2.6.	The MAP sensor

2.7.	The vacuum lines at the upper intake manifold

Refer to Intake Manifold Installation .

3. Install the rear generator brace. Refer to Generator Brace Replacement in Engine Electrical.
4. Connect the thermostat bypass pipe coolant hoses to the throttle body.
5. Connect the wiring harness connectors to the throttle body.

•	Throttle position (TP) sensor

•	Idle air control (IAC) valve

6. Install the accelerator control and cruise control cables with bracket to the throttle body. Refer to Accelerator Control Cable Bracket Replacement in Engine Controls - 3.4L.
7. Fill the cooling system with engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
8. Install the throttle body air inlet duct.
9. Connect the wiring harness connection to the intake air temperature (IAT) sensor in the throttle body air inlet duct. Refer to Intake Air Temperature Sensor Replacement in Engine Controls - 3.4L.
10. Connect the vacuum hose connection to the throttle body air inlet duct.
11. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.

Intake Manifold Replacement Lower

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 Disconnection and Connection in Engine Electrical.
2. Remove the upper intake manifold. Refer to Intake Manifold Replacement .
3. Remove the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
4. Remove the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .



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



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



7. Remove the fuel pipe clip bolt.



8. Remove the fuel pipe clip.



9. Disconnect the fuel feed pipe from the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.4L.



10. Disconnect the fuel return pipe from the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.4L.



11. Remove the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.4L.
12. Disconnect the power steering pump from the front engine cover and position aside. Refer to Power Steering Pump Replacement in Power Steering.
13. Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition.
14. Disconnect the radiator inlet hose from the engine. Refer to Radiator Inlet Hose Replacement in Engine Cooling.



15. Disconnect the thermostat bypass hose from the thermostat bypass pipe and lower intake manifold pipe.



16. Remove the lower intake manifold bolts and DISCARD the bolts.
17. Remove the lower intake manifold.
18. Remove the valve rocker arms and pushrods. Refer to Valve Rocker Arm and Push Rod Removal .



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



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



24. If replacing the lower intake manifold remove the water outlet bolts.
25. Remove the water outlet.



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

1. If removed install the thermostat.

Notice: Refer to Fastener Notice in the Preface section.




2. If removed install the water outlet.

Install the water outlet bolts. Refer to Water Outlet Installation .




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

Tighten
Tighten the engine coolant temperature (ECT) sensor to 23 N·m (17 lb ft).





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.

4. Install the lower intake manifold gaskets.
5. With gaskets in place supply 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 the intake manifold to block joint (1).
6. Connect the 2 small drops with a bead of RTV Sealer that is between 8-10 mm (0.30-0.39 in) wide and 3.0-5.0 mm (0.12-0.20 in) thick (2).
7. Install the valve rocker arms and pushrods. Refer to Valve Rocker Arm and Push Rod Replacement .

Notice: Refer to Fastener Notice in the Preface section.





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 the 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.

8. Install the lower intake manifold.

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 N·m (18 lb ft) on the final pass.



9. Connect the thermostat bypass hose to the thermostat bypass pipe and lower intake manifold pipe.
10. Connect the radiator inlet hose to the engine. Refer to Radiator Inlet Hose Replacement in Engine Cooling.



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 Power Steering System.




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

14. Install the fuel injector rail assembly.

14.1.

Install the fuel injector O-rings using GM P/N 12345616 (Canadian P/N 993182).

14.2.

Install the injector nozzles into the lower intake manifold injector bores.

14.3.

Press on the injector rail using the palms of both hands until the injectors are fully seated.

15. Install the fuel injector rail bolts.

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




16. Connect the fuel return pipe to the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.4L.



17. Connect the fuel feed pipe to the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.4L.



18. Install the fuel feed and return pipe retaining clip.
19. 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).




20. Connect the fuel injector and manifold air pressure (MAP) wiring harness.



21. Connect the engine coolant temperature (ECT) wiring harness.
22. Install the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
23. Install the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
24. Install the upper intake manifold. Refer to Intake Manifold Replacement .
25. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.