Exhaust Manifold Replacement - Left Side 4.3L Engine

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the exhaust manifold pipe nuts.
3. Lower the vehicle.



4. Remove the spark plug wire clip from the exhaust gas recirculation (EGR) valve inlet pipe tab.



5. Disconnect the spark plug wires from the spark plugs.
6. Remove the spark plug wire retainer bolts.
7. Position the wire harness on top of the engine.



8. Remove the spark plugs.



9. Remove the EGR valve inlet pipe from the intake and exhaust manifolds.



10. Disconnect the engine coolant temperature (ECT) sensor electrical connector.



11. Remove the exhaust manifold and spark plug wire shields bolts/stud.
12. Remove the exhaust manifold and plug wire shields.



13. Remove and discard the exhaust manifold gaskets.



14. Remove the exhaust manifold heat shield bolts and shield, if required.
15. Clean all gasket mating surfaces.

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.

1. Install the exhaust manifold heat shield and bolts, if required.

Tighten
Tighten the exhaust manifold heat shield bolts to 9 N·m (80 lb in).





Important: To assist in installing the exhaust manifold and gasket to the engine, tabs on a NEW exhaust manifold gasket will hold the gasket and bolts in place.

2. Install NEW exhaust manifold gaskets to the exhaust manifold.
3. Ensure that the exhaust manifold bolts/stud, and plug wire shields are held in place by the tabs on the exhaust manifold gaskets.



4. Install the exhaust manifold and plug wire shields.
5. If reusing the old fasteners, apply threadlock GM P/N United States 12345493, GM P/N Canada 10953488, or equivalent to the threads of the exhaust manifold bolts/stud.
6. Tighten the exhaust manifold bolts/stud.

Tighten
Tighten the exhaust manifold bolts/stud to 30 N·m (22 lb ft).




7. Connect the ECT sensor electrical connector.



8. Install the EGR valve inlet pipe to the intake and exhaust manifolds.

Tighten

•	Tighten the EGR valve inlet pipe fitting to the intake manifold to 25 N·m (18 lb ft).

•	Tighten the EGR valve inlet pipe fitting to the exhaust manifold to 30 N·m (22 lb ft).




9. Install the spark plugs.

Tighten
Tighten the spark plugs to 15 N·m (11 lb ft).




10. Position the wire harness to the engine.
11. Install the spark plug wire retainer bolts.

Tighten
Tighten the spark plug wire retainer bolts to 12 N·m (106 lb in).

12. Connect the spark plug wires to the spark plugs.



13. Install the spark plug wire clip to the EGR valve inlet pipe tab.
14. Raise the vehicle.



15. Install the exhaust manifold pipe nuts.

Tighten
Tighten the exhaust manifold pipe nuts to 50 N·m (37 lb ft).

16. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 4.8L, 5.3L, and 6.0L Engines

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Remove the exhaust manifold pipe nuts.
3. Lower the vehicle.
4. Remove the spark plugs. Refer to Spark Plug Replacement for the 4.8L, 5.3L, and 6.0L engines.



5. Remove the exhaust manifold bolts, manifold, and gasket. Discard the bolts.
6. Discard the gasket.



7. Remove the heat shield bolts (3), and shield (2) from the exhaust manifold (1), if necessary.
8. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection for the 4.8L, 5.3L engines, and 6.0L Unit Repair.

1. Install the exhaust manifold to the cylinder head. Refer to Exhaust Manifold Installation - Left Side .
2. Install the spark plugs. Refer to Spark Plug Replacement for the 4.8L, 5.3L, and 6.0L engines.
3. Raise the vehicle.

Notice: Refer to Fastener Notice in the Preface section.




4. Install the exhaust manifold pipe nuts.

Tighten
Tighten the exhaust manifold pipe nuts to 50 N·m (37 lb ft).

5. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 6.6L Engine

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the exhaust pipe heat shield bolts.
3. Reposition the heat shield to the side in order to access the exhaust pipe to exhaust manifold bolts.



4. Remove the exhaust pipe to exhaust manifold bolts (2).
5. Lower the vehicle in order to work through the front wheelhouse opening.
6. Remove the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.
7. Remove the front tire and wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
8. Remove the charged air cooler outlet duct. Refer to Charged Air Cooler Hoses/Pipes Replacement in Engine Mechanical - 6.6L.



9. Remove the exhaust manifold heat shield bolts.
10. Remove the exhaust manifold heat shield.



11. Remove the exhaust manifold bolts/nuts.
12. Remove the exhaust manifold.

12.1.

Remove the manifold from the rear stud.

12.2.

Remove the manifold from the front stud.

12.3.

Slide the manifold out the bottom, past the oil filter.

13. Remove and discard the exhaust manifold gasket.
14. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 6.6L Unit Repair.

1. Install the exhaust manifold with gasket.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the exhaust manifold bolts/nuts.



3. Use the sequence shown, to properly tighten the exhaust manifold bolts.

Tighten

1. Tighten the exhaust manifold bolts/nut a first pass to 34 N·m (25 lb ft).
2. Tighten the exhaust manifold bolts/nuts a final pass to 34 N·m (25 lb ft).



4. Install the exhaust manifold heat shield.
5. Install the exhaust manifold heat shield bolts.

Tighten
Tighten the exhaust manifold heat shield bolts to 8 N·m (71 lb in).




6. Install the exhaust pipe gasket. Align the tab on the gasket to face outward.
7. Install the exhaust pipe and the bolts (2) to the exhaust manifold.

Tighten
Tighten the exhaust pipe to exhaust manifold bolts to 53 N·m (39 lb ft).




8. Raise the vehicle.
9. Install the exhaust pipe heat shield bolts.

Tighten
Tighten the exhaust pipe heat shield bolts to 8 N·m (71 lb in).

10. Install the charged air cooler outlet duct. Refer to Charged Air Cooler Hoses/Pipes Replacement in Engine Mechanical - 6.6L.
11. Install the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.
12. Install the front tire and wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
13. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 8.1L Engine

1. Remove the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.

Important: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug wire or the wire could be damaged.

2. Remove the spark plug wires from the spark plugs and ignition coils.
3. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L.



4. Raise and suitably support the vehicle with safety stands. Refer to Lifting and Jacking the Vehicle in General Information.
5. Remove the exhaust manifold heat shield bolts and nuts.
6. Remove the left exhaust manifold heat shield.
7. Lower the vehicle.



8. Remove the exhaust manifold bolt and nuts.
9. Remove the exhaust manifold.
10. Remove and discard the exhaust manifold gasket.
11. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 8.1L Unit Repair.

1. Install a NEW exhaust manifold gasket.
2. Install the exhaust manifold.

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.

3. Install the exhaust manifold bolt and nuts.

Tighten

•	Tighten the exhaust manifold bolt to 35 N·m (26 lb ft).

•	Tighten the exhaust manifold nuts to 16 N·m (12 lb ft).

4. Raise the vehicle.



5. Install the exhaust manifold heat shield.
6. Install the exhaust manifold heat shield bolts and nuts.

Tighten
Tighten the heat shield bolts and nuts to 25 N·m (18 lb ft).

7. Lower the vehicle.
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L.




Important: Fully install the spark plug wire by pushing on the exposed end of the spark plug boot. Do not push the spark plug wire on to the spark plug by using the metal heat shield.

9. Install the spark plug wires to the spark plugs and ignition coils.
10. Install the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.