Lower Intake Manifold Replacement

CAUTION: 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.

REMOVAL
1. Disconnect the negative battery cable.
2. Drain the coolant. See Cooling System.
3. Remove the coolant recovery reservoir. See Cooling System.
4. Remove the accessory drive belt.
5. Remove the upper intake manifold.
6. Remove the fuel feed and return pipe from the manifold. See Powertrain Management.
7. Remove the fuel injector rail. See Powertrain Management.
8. Remove the power steering pump pulley. See Steering and Suspension.
9. Remove the power steering pump bolts. Move the power steering pump aside. See Steering and Suspension.





10. Disconnect the heater inlet pipe from the manifold.
11. Disconnect the upper radiator hose at the engine. See Cooling System.
12. Disconnect the straps from the heater outlet pipe and ignition wiring harness.
13. Disconnect the heater pipe from the heater core to water pump. See Heating and Air Conditioning.
14. Remove the valve valve cover.





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.

INSTALLATION
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 PIN 12345382 to the threads of the bolts.

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

5. Hand tighten the vertical bolts.
6. Hand tighten the diagonal bolts.
a. Tighten the Lower intake manifold center bolts to 7 Nm (62 inch lbs.)
b. Tighten the vertical bolts to 13 Nm (115 inch lbs.).
c. Tighten the diagonal bolts to 13 Nm (115 inch lbs.).
d. Tighten the lower intake manifold diagonal bolt to 25 Nm (18 ft. lbs.)

7. Install the valve valve cover.
8. Connect the heater pipe from heater core to water pump. See Heating and Air Conditioning.
9. Connect the tie straps around the heater outlet pipe and ignition wiring harness.
10. Connect the upper radiator hose at the engine. See Cooling System.
11. Connect the heater inlet pipe to the manifold.
12. Position the power steering pump. See Steering and Suspension.
13. Install the power steering pump bolts. See Steering and Suspension.
14. Install the power steering pump pulley. See Steering and Suspension.
15. Install the fuel injector rail. See Powertrain Management.
16. Connect the fuel feed and return pipe to the manifold. See Powertrain Management.
17. Install the upper intake manifold.
18. Install the accessory drive belt.
19. Install the coolant recovery reservoir. See Cooling System.
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. See Cooling System.