Lower Intake Manifold Replacement

TOOL REQUIRED
^ J 28467-360 Engine Support Fixture

REMOVAL
1. Disconnect the negative battery cable.
2. Depressurize the fuel system. See Powertrain Management.
3. Remove the top half of the air cleaner assembly.
4. Drain and recover the cooling system. See Cooling System.





5. Remove the EGR pipe from the exhaust manifold.
6. Remove the drive belt.
7. Remove the brake vacuum pipe at the plenum.
8. Remove the power steering lines at the generator bracket.
9. Remove the generator. See Starting and Charging.





10. Remove the secondary ignition wires from the spark plugs.
11. Remove the secondary ignition wires from the harness at the plenum.
12. Remove the following components at the same time:
^ Electronic ignition coil and module assembly
^ EVAP canister purge solenoid
13. Remove the following upper engine wiring connectors:
^ Throttle Position (TP) sensor
^ IAC sensor
^ Injector harness
^ Engine Coolant Temperature (ECT) sensor
^ MAP sensor
^ Camshaft Position (CMP) sensor
14. Remove the following vacuum lines:
^ Vacuum Modulator
^ Fuel Pressure Regulator
^ PCV
15. Remove the, MAP sensor from the upper intake manifold.





16. Remove the upper intake manifold bolts.
17. Remove the upper intake manifold.





18. Remove the fuel lines at the fuel rail and the bracket.
19. Install the Engine Support Fixture.
20. Remove the engine mount assembly.
21. Remove the power steering mounting bolts. Support the pump aside. See Steering and Suspension.
22. Remove the coolant inlet pipe from the coolant outlet housing. See Cooling System.
23. Remove the coolant by-pass at the coolant pump and the cylinder head. See Cooling System.
24. Remove the radiator hose at the coolant outlet housing.
25. Remove the coolant outlet housing. See Cooling System.
26. Remove both of the valve rocker covers.

NOTE: Retain the washers in the same orientation on the center bolts.





27. Remove the lower intake manifold bolts.
28. Remove the lower intake manifold.





29. Loosen the rocker arms.

CAUTION: Keep the pushrods in order. The pushrods must be installed in the original position.





30. Remove the pushrods.
31. Remove the intake gasket.
32. Inspect the flatness of the inlet flanges.
33. Clean the following items:
^ Gasket material from the mating surfaces
^ Excess RTV sealant from the front and the rear ridges of the cylinder
^ Block
^ Sealing surfaces with degreaser

INSTALLATION
1. Place a 2-3 mm bead of GM RTV sealer P/N 1052917, or equivalent on each ridge where the front and the rear of the intake manifold contact the block.
2. Install the intake manifold gasket.
3. Install the pushrods.
a. Install the pushrods in their original location.
b. Coat the ends of the pushrods with prelube GM P/N 1052356, or equivalent.
c. Intake pushrods are marked yellow and are 5 3/4 inch long.
d. Exhaust pushrods are marked green and are 6 in long.
e. Ensure that the pushrods seat in the lifter.
4. Install the rocker arm bolts. Tighten the bolts to 14 Nm (124 lb in) + 30°.
5. Install the lower intake manifold.
6. Install the lower intake manifold bolts. Apply sealant GM P/N 12345739 to the threads of the bolts.

Notice: The OEM service manual does not provide a torque sequence for the upper or lower intake manifolds.

a. First, tighten the vertical bolts to 13 Nm (115 lb in).
b. Then, tighten the diagonal bolts to 13 Nm (115 lb in).
7. Install the front valve rocker cover.
8. Install the coolant outlet housing. See Cooling System.
9. Install the radiator hose to the thermostat housing.
10. Install the coolant inlet pipe to the thermostat housing.
11. Install the coolant by-pass pipe at the coolant pump and the cylinder head. See Cooling System.
12. Install the power steering pump. See Steering and Suspension.
13. Loosely, install the drive belt.
14. Install the engine mount assembly.
15. Remove the engine support fixture.
16. Install the fuel lines to the fuel rail and the bracket.
17. Install the upper intake manifold.
18. Install the upper intake manifold bolts. Tighten the bolts to 25 Nm (18 lb ft).
19. Install the MAP sensor.
20. Connect the following vacuum lines:
^ Vacuum Modulator
^ Fuel Pressure Regulator
^ PCV
21. Install the following upper engine wiring connectors:
^ TP sensor
^ IAC
^ Injector harness
^ ECT sensor
^ MAP sensor
^ CMP sensor
22. Install the following components:
^ EVAP canister purge solenoid
^ Electronic ignition coil and module assembly
23. Install the generator. See Starting and Charging.
24. Install the power steering line at the generator bracket.
25. Install the drive belt.
26. Install the secondary ignition wires to the spark plugs.
27. Install the secondary ignition wires to the harness at the plenum.
28. Install the EGR pipe to the exhaust manifold.
29. Install the following items to the throttle body:
^ Throttle body cable
^ Cruise control cable
30. Install the top half of the air cleaner assembly.
31. Install the brake vacuum pipe.
32. Install the cables to the throttle body.
33. Fill the cooling system. See Cooling System.
34. Connect the negative battery cable.
35. Inspect for proper fluid levels.
36. Check for leaks.