For 1990-2009 cars

## Intake Manifold Replacement Upper

### Removal Procedure

1. Disconnect the negative battery cable. Refer to

   Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

   in General Information.
2. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
3. Remove the drive belt. Refer to Drive Belt Replacement .
4. Remove the transmission level indicator, if necessary.
5. Remove the generator. Refer to Generator Replacement in Engine Electrical.
6. Remove the drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
7. Remove the MAP sensor.
8. Remove the vacuum source from the upper intake manifold.
9. Remove the evaporative emissions canister purge solenoid valve.
10. Remove the fuel pressure regulator and canister purge harness.
11. Remove the idle air control (IAC) valve from the upper intake manifold.
12. Relieve the fuel pressure.
13. Remove the fuel lines from the fuel rail.
14. Remove the accelerator control cable bracket bolts and the bracket from the throttle body. Remove the accelerator control cables from the throttle body.
15. Remove the ignition control module.
16. Remove the brake booster hose from the upper intake manifold. Refer to SECTION 5D1.
17. Remove the generator brace from the upper intake manifold.
18. Remove the electrical connectors at the following locations:

• | The idle air control

• | The throttle position sensor

• | The mass airflow sensor

• | The intake air temperature sensor

19. Remove the wiring harness from the rosebud clips at the fuel rail.
20. Remove the air cleaner. Remove the air cleaner outlet rear duct. Remove the resonator duct.
21. Remove the throttle body from the upper intake manifold, if necessary.
22. Remove the EGR valve outlet pipe.

Important: The thermostat housing must be removed in order to access the hidde bolt or screw located under the housing. The hidden bolt or screw secures the upper and lower intake manifolds together.

23. Remove the thermostat and thermostat housing. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.
24. Remove the electrical connectors from the fuel injectors.

Important: Clean the dirt out of injector bores with compressed air.

25. Remove the fuel rail nuts.
26. Remove the fuel rail.
27. Remove the upper intake manifold bolts.
28. Remove the upper intake manifold.

### Installation Procedure

1. Install the upper intake manifold gasket.
2. Install the upper intake manifold.
3. Install the upper intake manifold bolts.

Tighten

1. Tighten in sequence the ten vertical intake manifold bolts to 15 N·m (11 lb ft).
2. Tighten the two water outlet bolts to 27 N·m (20 lb ft).
3. Tighten the side bolts to 30 N·m (22 lb ft).

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.

4. Use the following procedure to install the fuel rail:

4.1. | Using clean engine oil, lightly lubricate the fuel injector O rings.

4.2. | Install the injectors of the rail into the bores of the manifold.

4.3. | Carefully press the fuel rail with the palms of both hands until the injectors are fully seated.

5. Install the fuel rail nuts.

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

6. Install the electrical connectors to the fuel injectors.
7. Install the thermostat and thermostat housing. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.
8. Install the EGR valve outlet pipe.
9. Install the throttle body to the upper intake manifold, if necessary.
10. Install the air cleaner. Install the air cleaner outlet duct. Install the resonator duct.
11. Connect the wiring harness to the rosebud clips at the fuel rail.
12. Install the electrical connectors at the following locations:

• | The idle air control

• | The throttle position sensor

• | The mass airflow sensor

• | The intake air temperature sensor.

13. Install the generator brace to the upper intake manifold.
14. Install the brake booster hose to the upper intake manifold .
15. Install the ignition control module.
16. Install the accelerator control cable bracket to the throttle body. Install the accelerator control cables to the throttle body.
17. Install the accelerator control cable bracket bolts.

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

18. Install the fuel lines to the fuel rail.
19. Install the IAC valve to the upper intake manifold.
20. Install the fuel pressure regulator and the canister purge harness.
21. Install the MAP sensor.
22. Install the vacuum source to the upper intake manifold.
23. Install the drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
24. Install the generator. Refer to Generator Replacement in Engine Electrical.
25. Install the transmission level indicator, if necessary.
26. Install the drive belt. Refer to Drive Belt Replacement .
27. Refill the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
28. Connect the negative battery cable.

## Intake Manifold Replacement Lower

### Removal Procedure

Important: Remove the upper intake manifold in order to uncover the hidden bolts on the front and left rear corners of the lower intake manifold.

1. Remove the upper intake manifold. Refer to Intake Manifold Replacement .
2. Remove the engine coolant temperature sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.
3. Remove the lower intake manifold bolts.
4. Remove the lower intake manifold.
5. Remove the lower intake manifold gaskets and seals.

### Installation Procedure

1. Apply GM P/N 12345336 or equivalent to both the front and rear intake manifold seals.
2. Install the intake manifold gaskets and seals.
3. Install the lower intake manifold.

Important: The two lower intake manifold bolts are located under the upper intake manifold. They must be installed before the upper intake manifold.

4. Apply GM P/N 12345493 or equivalent thread lock compound to the bolt threads before installing.
5. Install the lower intake manifold bolts.

Tighten
Tighten the lower manifold bolts in sequence to 15 N·m (11 lb ft).

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.

6. Install the engine coolant temperature sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.
7. Install the upper intake manifold. Refer to Intake Manifold Replacement .