Intake Manifold Replacement (Lower)
REMOVAL PROCEDURECAUTION: Refer to Battery Disconnect Caution in Service Precautions.
1. Disconnect the battery negative cable.
2. Drain the engine coolant.
3. Remove the air cleaner assembly.
4. Remove the following coolant hoses:
- Upper radiator hose.
- Both heater hoses.
- Coolant by-pass hose.
5. Disconnect all electrical connectors.
6. Remove the distributor.
7. Use a twisting motion to remove the vacuum brake booster hose, if equipped.
8. Disconnect the throttle cable and the cruise control cable, if equipped.
9. Remove the drive belt.
IMPORTANT: It is not necessary to discharge the A/C refrigerant.
10. Remove the air conditioning (A/C) compressor, if equipped, and set it aside.
11. Disconnect the exhaust gas recirculation (EGR) pipe from the bracket and the front of the intake manifold.
12. Remove the PCV valve.
13. Disconnect the fuel pipes from the rear of the intake manifold.
14. Disconnect the electrical connector from the power steering pump.
15. Remove the power steering pump mounting bracket using the following procedure:
- Remove the power steering pump pulley.
- Remove the nut, then the bolts.
- Remove two nuts from the back of the power steering pump.
- Slide the power steering pump mounting bracket forward, with the power steering pump still attached.
16. Disconnect the wiring bracket from the rear of the right cylinder head.
17. Remove one valve rocker arm cover.
18. Remove the intake manifold bolts.
19. Remove the intake manifold. Refer to Intake Manifold Removal under Engine Unit Repair.
20. Clean all surfaces. Refer to Intake Manifold Clean and Inspect under Engine Unit Repair.
INSTALLATION PROCEDURE
NOTICE: Applying excessive amounts of sealant may prohibit the intake gasket from sealing properly.
IMPORTANT: The lower intake manifold must be installed and the fasteners tightened while the adhesive is still wet to the touch.
1. Apply a 4.0 mm (0.157 inch) patch of adhesive GM P/N 12346141 or equivalent to the cylinder head side of the lower intake manifold gasket at each end.
2. Install the lower intake manifold gasket onto the cylinder head.
Use the gasket locator pins in order to properly seat the lower intake manifold gasket onto the cylinder head.
NOTICE: Care must be used to apply the correct amount of sealant onto the gaskets. Applying excessive amounts of sealant may prohibit the intake gaskets from sealing properly.
IMPORTANT: All sealing surfaces must be clean, free of oil, dirt, or any other foreign material.
3. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the front top of the engine block.
4. Extend the adhesive bead 13 mm (0.50 inch) onto the each lower intake manifold gasket.
5. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the rear top of the engine block.
6. Extend the adhesive bead 13 mm (0.50 inch) onto each lower intake manifold gasket.
7. Install the lower intake manifold onto the engine block and the cylinder heads.
NOTICE: Refer to Fastener Notice in Service Precautions.
8. Apply threadlock GM P/N 12345382 or equivalent to the threads of the lower intake manifold bolts.
NOTICE: Proper lower intake manifold fastener tightening sequence and torque is critical. Always follow the tightening sequence, and torque the intake manifold bolts using the 3 step method. Failing to do so may distort the crankshaft bearing bore alignment and cause damage to the crankshaft bearings.
9. Install the lower intake manifold bolts.
9.1. Tighten the bolts on the first pass in sequence (1-8) to 3 Nm (27 inch lbs.).
9.2. Tighten the bolts on the second pass in sequence (1-8) to 12 Nm (106 inch lbs.).
9.3. Tighten the bolts on the final pass in sequence (1 -8) to 15 Nm (11 ft. lbs.).
10. Connect the evaporative emission (EVAP) canister purge solenoid valve harness.
10.1. Push the elbow inward until the quick connect snaps into place.
10.2. Pull the elbow outward in order to ensure proper connection.
11. Install the valve rocker arm cover.
NOTICE: Refer to Fastener Notice in Service Precautions.
12. Install the power steering pump bracket using the following procedure:
- Install the power steering pump bracket onto the stud.
- Install the nut onto the stud finger tight.
- Install the three bolts finger tight.
- Install the two nuts to the back of the power steering pump.
- Install the three bolts.
Tighten the nuts and the bolts to 41 Nm (30 ft. lbs.).
- Install the power steering pump pulley.
- Connect the electrical connector to the power steering pump.
- Connect the fuel pipes to the rear of the intake manifold.
- Connect the wiring bracket to the rear of the right cylinder head.
- Install the PCV valve.
13. Connect the exhaust gas recirculation (EGR) pipe to the bracket and the front of the intake manifold.
14. Use a twisting motion to install the vacuum brake booster hose, if equipped.
15. Install the air conditioning (A/C) compressor, if equipped.
16. Install the drive belt.
17. Connect the throttle cable and the cruise control cable, if equipped.
18. Install the distributor.
19. Connect all electrical connectors.
20. Install the following coolant hoses:
- Upper radiator hose.
- Both heater hoses.
- Coolant by-pass hose.
21. Install the air cleaner assembly.
22. Fill the engine cooling system with coolant.
23. Connect the battery negative cable.