Intake Manifold Replacement - Lower
Intake Manifold Replacement - LowerRemoval Procedure
Important: You do not have to remove the upper intake manifold in order to remove the lower intake manifold.
1. Disconnect the battery negative cable.
2. Remove the engine cover.
3. Drain the cooling system.
4. Remove the retaining nut (1) from the air cleaner outlet.
5. Remove the air cleaner outlet duct (2) from the throttle body assembly.
6. Disconnect the harness connector of the Intake Air Temperature (IAT) sensor.
7. Loosen the air cleaner outlet duct from the Mass Air Flow (MAF) sensor.
8. Remove the air cleaner outlet duct.
9. Remove the air cleaner assembly.
10. Disconnect the accelerator control cable from the throttle shaft and the accelerator control cable bracket.
11. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator control cable bracket.
12. Disconnect the PCV valve hose assembly from the intake manifold and the valve rocker arm cover.
13. Disconnect the following electrical connectors:
^ The Throttle Position (TP) sensor (1)
^ The Idle Air Control (IAC) motor (2)
^ The Engine Coolant Temperature (ECT) gauge sensor(3)
^ The A/C high pressure switch (4), if equipped
14. Disconnect the following electrical connectors:
^ The fuel meter body assembly connector (1)
^ The EVAP canister purge solenoid valve (2)
^ The Manifold Absolute Pressure (MAP) sensor(3)
15. Disconnect the following electrical connectors:
^ The A/C compressor clutch (1), if equipped
^ The EGR valve (2)
^ The Engine Coolant Temperature (ECT) sensor(3)
16. Remove the ground wire (4) from the stud at the water outlet.
17. Remove the radiator inlet hose at the water outlet.
18. Remove the heater hose from the intake manifold.
19. Remove the water pump inlet hose from the intake manifold.
20. Disconnect the A/C vacuum hose from the intake manifold.
21. Disconnect the power brake booster vacuum hose from the intake manifold.
22. Remove the power brake booster vacuum hose bracket and nut.
23. Remove the accelerator control cable bracket from the throttle body and the intake manifold.
24. Remove the EVAP canister purge solenoid valve.
25. Remove the distributor.
26. Disconnect the fuel supply and the return pipes at the rear of the intake manifold.
27. Remove the Ignition Control Module (ECM).
28. Remove the spark plug wire harness retainer from the Exhaust Gas Recirculation (EGR) valve inlet pipe.
29. Remove the clamp bolt for the EGR valve inlet pipe.
30. Remove the EGR valve inlet pipe from the intake and the exhaust manifolds.
31. In order to remove the front intake manifold bolt, perform the following:
31.1. Remove the auxiliary evaporator tube from the A/C compressor, if equipped.
31.2. Remove the drive belt.
31.3. Loosen the nut for the power steering pump rear bracket.
31.4. Remove the bolts and the nut for the power steering pump mounting bracket.
31.5. Leave the A/C compressor, if equipped, and the power steering pump on the bracket.
31.6. Slide the power steering pump bracket forward to access the bolt at the front of the intake manifold.
32. Remove the Engine Coolant Temperature (ECT) sensor wire connector (if equipped) from the engine wiring harness bracket.
33. Remove the lower intake manifold bolts.
Important: The intake manifold may be removed as an assembly.
Do not remove the specific intake manifold components unless component service is required.
Do not allow dirt or debris to enter the fuel system. Ensure that the ends of the fuel system are properly sealed.
Do not disassemble the Central Sequential Fuel Injection (SFI) unit, unless service is required.
34. Remove the intake manifold assembly.
35. Remove and discard the lower intake manifold gaskets.
36. Clean all sealing surfaces and the intake manifold.
37. If the intake manifold requires replacement refer to Intake Manifold Disassemble and Intake Manifold Assemble.
Installation Procedure
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.
Important: The lower intake manifold gasket must be installed while the adhesive is still wet to the touch.
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 on the cylinder head.
Important: The lower intake manifold must be installed and the fasteners tightened while the adhesive is still wet to the touch.
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 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.
8. If reusing the fasteners, apply threadlock GM P/N 12345382 or equivalent to the threads of the lower intake manifold bolts.
9. Install the lower intake manifold bolts.
Notice: Refer to Fastener Notice in Service Precautions.
10. Tighten the lower intake manifold bolts.
10.1. Tighten the bolts on the first pass in sequence (1-8) to 3 Nm (27 inch lbs.).
10.2. Tighten the bolts on the second pass in sequence (1-8) to 12 Nm (106 inch lbs.).
10.3. Tighten the bolts on the final pass in sequence (1-8) to 15 Nm (11 ft. lbs.).
11. Reposition the power steering pump mounting bracket.
12. Install the power steering pump mounting bracket three bolts and the nut.
^ Tighten the power steering pump mounting bracket bolts and the nut and the power steering pump rear bracket nut to 41 Nm (30 ft. lbs.).
13. Install the drive belt.
14. Install the auxiliary evaporator tube to the A/C compressor, if equipped.
15. Install the Exhaust Gas Recirculation (EGR) valve inlet pipe to the intake and the exhaust manifolds.
16. Install the EVAP canister purge solenoid valve.
17. Install the fuel supply and return pipes to the rear of the intake manifold.
Important: In order to install the distributor for the correct engine timing, position the engine to number one cylinder top dead center.
18. Remove the spark plug for number one cylinder.
19. Rotate the crankshaft until number one cylinder is in the compression stroke.
20. Align the two reference marks on the crankshaft balancer (1) and (4) with the two alignment marks (2) and (3) on the front cover.
21. Install the spark plug.
22. Install the distributor.
23. Install the ECM.
24. Install the accelerator control cable bracket, studs, and nuts to the intake manifold and the throttle body.
^ Tighten the accelerator control cable bracket nuts and studs to 12 Nm (106 inch lbs.).
25. Install the power brake booster vacuum hose bracket to the intake manifold stud.
^ Tighten the bracket nut to 11 Nm (97 inch lbs.).
26. Connect the power brake booster vacuum hose to the intake manifold.
27. Install the A/C vacuum hose to the intake manifold.
28. Install the water pump inlet hose to the intake manifold.
29. Install the heater hoses.
30. Install the radiator inlet hose to the water outlet.
31. Connect the following electrical connectors:
^ The Throttle Position (TP) sensor (1)
^ The Idle Air Control (IAC) motor (2)
^ The Engine Coolant Temperature (ECT) gauge sensor(3)
^ The A/C high pressure switch (4), if equipped
32. Connect the following electrical connectors:
^ The fuel meter body assembly connector (1)
^ The EVAP canister purge solenoid valve (2)
^ The Manifold Absolute Pressure (MAP) sensor(3)
33. Connect the following electrical connectors:
^ The A/C compressor clutch (1), if equipped
^ The EGR valve (2)
^ The Engine Coolant Temperature (ECT) sensor(3)
34. Install the ground wire (4) and the nut to the water outlet stud.
^ Tighten the ground wire nut to 10 Nm (88 inch lbs.).
35. Install the PCV valve hose assembly to the intake manifold and the valve rocker arm cover.
36. Install the cruise control cable, if equipped to the throttle shaft and the accelerator control cable bracket.
37. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket.
38. Refill the cooling system.
Notice: Refer to Mass Air Flow (MAF) Handling Notice in Service Precautions.
39. Install the air cleaner outlet duct to the MAF sensor.
40. Connect the IAT sensor harness connector.
41. Install the air cleaner outlet duct (2) on the throttle body assembly.
42. Tighten the retaining nut (1).
^ Tighten the nut 2 Nm (18 inch lbs.).
43. Install the air cleaner assembly.
44. Connect the battery negative cable.
45. Install the engine cover.