Intake Manifold Replacement - Lower
Removal ProcedureNotice: The two bolts which fasten the lower intake manifold to the cylinder head are accessible only after the upper intake is removed. The bolts are located in the right front and left rear corners of the lower intake manifold. Remove the upper intake manifold to service the lower intake.
1. Remove the upper intake manifold. Refer to Intake Manifold Replacement.
2. Remove the generator brace. Refer to Generator Brace Replacement.
3. Remove the generator. Refer to Generator Replacement.
4. Remove the drive belt tensioner with mounting bracket and the heater water bypass inlet pipe.
Refer to Drive Belt Tensioner Replacement.
5. Remove the EGR tube from the lower intake manifold.
6. Remove the radiator inlet hose from the water outlet housing. Refer to Radiator Hose Replacement - Inlet in Cooling System.
7. Remove the engine coolant temperature (ECT) sensor wiring harness connector.
8. Remove the generator brace bracket bolts.
9. Remove the generator brace bracket.
10. Remove the evaporative emissions canister purge solenoid valve. Refer to EVAP Canister Purge Valve Replacement.
11. Remove the lower intake manifold bolts.
12. Remove the lower intake manifold.
13. Remove the lower intake manifold seals.
14. Remove the lower intake manifold gaskets.
15. If replacing the lower intake manifold, remove the water outlet housing bolts, the water outlet housing, the gasket and the thermostat. Refer to Thermostat Replacement in Cooling System.
16. If replacing the lower intake manifold, remove the engine coolant temperature (ECT) sensor. Refer to Engine Coolant Temperature (ECT) Sensor Replacement.
17. Inspect the flatness of inlet flanges.
18. Clean the engine block.
19. Clean the cylinder block, heads, and the intake manifold sealing surface with a suitable solvent.
20. Clean the intake manifold bolts and bolt holes of adhesive compound.
Installation Procedure
Notice: Refer to Fastener Notice in Service Precautions.
1. If removed, install the engine coolant temperature (ECT) sensor.
^ Tighten the engine coolant temperature (ECT) sensor to 25 Nm (18 ft. lbs.).
2. If removed, install the thermostat, the gasket, and the water outlet housing. Refer to Thermostat Replacement in Cooling System.
3. Install the lower intake manifold gaskets.
4. Apply sealer GM P/N 12345336 or equivalent to the ends of the intake manifold seals.
5. Install the lower intake manifold seals.
Notice: The two bolts which fasten the lower intake manifold to the cylinder head are accessible only after the upper intake is removed. The bolts are located in the right front and left rear corners of the lower intake manifold. Remove the upper intake manifold to service the lower intake.
6. Install the lower intake manifold.
7. Install the lower intake manifold bolts (1-12). Apply thread lock compound GM P/N 12345382 or equivalent to the two hidden bolts and ensure they are installed.
^ Tighten the lower intake manifold bolts in sequence to 15 Nm (11 ft. lbs.).
8. Install the generator brace bracket.
9. Install the generator brace bracket bolts.
^ Tighten the generator brace bracket bolts to 50 Nm (37 ft. lbs.).
10. Install the evaporative emissions canister purge solenoid valve.
11. Install the engine coolant (ECT) temperature sensor wiring harness connector.
12. Install the radiator inlet hose to the water outlet housing. Refer to Radiator Hose Replacement -Inlet in Cooling System.
13. Install the drive belt tensioner mounting bracket and the water heater bypass inlet pipe to the drive belt tensioner mounting bracket. Refer to Drive Belt Tensioner Replacement.
14. Install the EGR tube to the lower intake manifold.
^ Tighten the EGR tube bolt to 29 Nm (21 ft. lbs.).
15. Install the generator brace. Refer to Generator Brace Replacement.
16. Install the generator. Refer to Generator Replacement.
17. Install the upper intake manifold. Refer to Intake Manifold Replacement.