Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

1. Remove the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 8.1 L.
2. Remove the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 8.1 L.
3. Remove the air cleaner bracket bolts.
4. Remove the air cleaner bracket.



5. Remove the purge solenoid bolt and purge solenoid.
6. Inspect the purge solenoid seal for damage. Replace the seal as needed.



7. Remove the manifold absolute pressure (MAP) sensor bolt and sensor.
8. Inspect the MAP sensor seal for damage.



9. Remove the oil fill tube bracket bolt.
10. Remove the oil fill tube from the intake manifold.



11. Remove the intake manifold bolts.

Important: Do not attempt to loosen the manifold by prying under the gasket surface with any tool.

12. Remove the intake manifold.




Important: The intake manifold gaskets are not reusable.

13. Remove and discard the intake manifold side gaskets.



14. Remove and discard the intake manifold end gaskets.




Important: The oil splash shield is secured using a snap-in fit. Do not distort the splash shield. The shield is reusable.

15. Remove the intake manifold oil splash shield.
16. Clean and inspect the intake manifold. Refer to Intake Manifold Cleaning and Inspection in Engine Mechanical - 8.1 L.

1. Install the intake manifold oil splash shield.



2. Ensure the splash shield (2) snap fits between the cylinder heads (1).



3. Install the new intake manifold end gaskets.



4. Install the new intake manifold side gaskets.



5. Ensure the intake manifold gasket tabs align with the hole in the head gasket.
6. Ensure the intake manifold gasket tabs align with the slot in the intake manifold end gaskets.



7. Install the intake manifold.



8. Apply threadlock GM P/N 12345382, Canada P/N 10953489, or equivalent to a minimum of eight threads of the intake manifold bolts.

Important: 

•	The entire intake manifold tightening sequence must be followed exactly, or an oil leak resulting in engine damage may occur. Ensure the intake manifold is tightened without allowing the intake manifold to shift.

•	The entire intake manifold tightening sequence must be promptly completed due to the anaerobic thread adhesive. The final pass of the tightening sequence must be completed before the adhesive starts to cure, or false torque readings and ineffective thread locking may result.

9. Install the intake manifold bolts.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

10. Tighten the intake manifold bolts in sequence, using four passes.

Tighten

1. Tighten the intake manifold bolts in sequence to 5 N·m (44 lb in) on the first pass.
2. Tighten the intake manifold bolts in sequence to 5 N·m (44 lb in) on the second pass. Inspect the intake manifold joints for signs of intake manifold shifting. Correct as required.
3. Tighten the intake manifold bolts in sequence to 10 N·m (89 lb in) on the third pass.
4. Tighten the intake manifold bolts in sequence to 12 N·m (106 lb in) on the final pass.



11. Apply sealant GM P/N 12377901, Canada P/N 10953504, or equivalent around the oil fill tube 19.05 mm (0.75 in) from the bottom.
12. Install the oil fill tube to the intake manifold.
13. Install the oil fill tube bracket bolt.

Tighten
Tighten the oil fill tube bracket bolt to 12 N·m (106 lb in).





Important: Lubricate the port of the MAP sensor with clean engine oil. Avoid dipping the sensor port directly into the lubricant or using a solid type of lubricant, as they may block the vacuum port signal.

14. Install the MAP sensor.
15. Install the MAP sensor bolt.

Tighten
Tighten the MAP sensor bolt to 12 N·m (106 lb in).




16. Apply a very light film of clean engine oil to the purge solenoid seal.
17. Install the purge solenoid.
18. Apply thread sealant GM P/N 12345493, Canada P/N 10953488, or equivalent to the threads of the purge solenoid bolt.
19. Install the purge solenoid bolt.

Tighten
Tighten the purge solenoid bolt to 10 N·m (89 lb in).




20. Install the air cleaner bracket.
21. Install the air cleaner bracket bolts.

Tighten
Tighten the air cleaner bracket bolts to 9 N·m (80 lb in).

22. Install the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 8.1 L.
23. Install the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 8.1 L.