For 1990-2009 cars

### 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. For the correct injector wiring harness connector-to-fuel injector connection procedure, refer to Engine Electrical.

1. Disconnect the battery ground (negative) 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. Remove the upper intake manifold. Refer to Upper Intake Manifold Replacement .
3. Remove the left (front) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
4. Remove the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
5. Remove the fuel feed and return pipe from the fuel injector rail. Refer to Engine Controls.
6. Remove the fuel injector rail. Refer to Engine Controls.
7. Remove the power steering pump from the front engine cover and reposition aside. Refer to Power Steering Gear and Pump.
8. Disconnect the heater inlet pipe from the lower intake manifold. Refer to HVAC.
9. Disconnect the upper radiator hose from the engine. Refer to Cooling and Radiator.
10. Remove the lower intake manifold bolts and DISCARD the bolts.
11. Remove the lower intake manifold.
12. Remove the lower intake manifold gaskets and seals.
13. Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
14. Clean the gasket and seal surfaces on the lower intake manifold with a degreaser.
15. Remove all the loose RTV sealer.

### Installation Procedure

1. Apply 8-12-mm (0.08-0.11-inch) bead of RTV Sealer GM P/N 12346141 (Canadian P/N 89022195) or equivalent on each ridge where front and rear of the lower intake manifold contact the engine block (1).
2. Install the lower intake manifold gaskets.
3. Install the lower intake manifold.
4. Install NEW intake manifold bolts.

Notice: An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.

5. Hand tighten the vertical bolts.

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. Hand tighten the diagonal bolts.

Tighten

1. Tighten the vertical lower intake manifold bolts to 7 N·m (62 lb in).
2. Tighten the diagonal lower intake manifold bolts to 7 N·m (62 lb in).
3. Tighten the vertical lower intake manifold bolts to 13 N·m (115 lb in).
4. Tighten the diagonal lower intake manifold bolts to 25 N·m (18 lb ft).

7. Connect the upper radiator hose to the engine. Refer to Cooling and Radiator.
8. Connect the heater inlet pipe to the lower intake manifold. Refer to HVAC.
9. Install the power steering pump to the front engine cover. Refer to Power Steering Gear and Pump.
10. Install the fuel injector rail. Refer to Engine Controls.
11. Connect the fuel feed and return pipe to the fuel injector rail. Refer to Engine Controls.
12. Install the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
13. Install the left (front) valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
14. Install the upper intake manifold. Refer to Upper Intake Manifold Replacement .
15. Connect the battery ground (negative) cable. Refer to Battery.