Important: This engine uses a sequential multiport fuel injection system. Injector connectors must be connected to their appropriate fuel injector or exhaust emissions and engine performance may be seriously affected. For the correct connector to injector connection procedure, refer to SECTION 8A.

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.

1. Disconnect the negative battery cable.
2. Drain the coolant.
3. Remove the coolant recovery reservoir. Refer to SECTION 6B.
4. Remove the accessory drive belt. Refer to Drive Belt Replacement .
5. Remove the upper intake manifold. Refer to Upper Intake Manifold Replacement .
6. Remove the fuel feed and return pipe from the manifold.
7. Remove the fuel injector rail.



8. Remove the power steering pump pulley. Refer to SECTION 3B.
9. Remove the power steering pump bolts. Move the power steering pump aside. Refer to SECTION 3B.



10. Disconnect the heater inlet pipe from the manifold.
11. Disconnect the upper radiator hose at the engine.
12. Disconnect the straps from the heater outlet pipe and ignition wiring harness.
13. Disconnect the heater pipe from the heater core to coolant pump.
14. Remove the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .



15. Remove the bolts.
16. Remove the lower intake manifold.
17. Remove the gasket.
18. Clean the gasket and seal surfaces on the manifold with degreaser.
19. Remove all the loose RTV sealer.

1. Apply 8-12 mm (0.08-0.11 inch) bead of RTV Sealer, GM P/N 12345739 or equivalent, on each ridge where front and rear of the manifold contact the engine block.
2. Install the lower intake manifold gaskets.
3. Install the lower intake manifold.
4. Apply sealant, GM P/N 12345382 to the threads of the 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 bolts to 13 N·m (115 lb in).
2. Tighten the diagonal bolts to 13 N·m (115 lb in).
7. Install the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
8. Connect the heater pipe from heater core to coolant pump.
9. Connect the tie straps around the heater outlet pipe and ignition wiring harness.
10. Connect the upper radiator hose at the engine.



11. Connect the heater inlet pipe to the manifold.



12. Position the power steering pump. Refer to SECTION 3B.
13. Install the power steering pump bolts. Refer to SECTION 3B.
14. Install the power steering pump pulley. Refer to SECTION 3B.
15. Install the fuel injector rail.
16. Connect the fuel feed and return pipe to the manifold.
17. Install the upper intake manifold. Refer to Upper Intake Manifold Replacement .
18. Install the accessory drive belt. Refer to Drive Belt Replacement .
19. Install the coolant recovery reservoir. Refer to SECTION 6B.
20. Refill the coolant recovery reservoir with engine coolant. Add two engine coolant sealant pellets, GM P/N 3634621, or equivalent.
21. Bleed the engine cooling system. Refer to SECTION 6B.