1. Remove the heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .
2. Fully raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
3. Remove the catalytic converter to exhaust manifold nuts. (1500 series shown, 2500 series similar).
4. Remove the front wheel house liner - right side. Refer to Front Wheelhouse Liner Replacement - Right Side .



5. Partially lower the vehicle in order to work through the wheel opening.
6. Remove the spark plug wires (1) from the spark plugs.

6.1.	Twist the spark plug wire boot a 1/2 turn.

6.2.	Pull only on the boot in order to remove the wire from the spark plug.

7. Remove the spark plug wires from the ignition coils.

7.1.	Twist the spark plug wire boot a 1/2 turn.

7.2.	Pull only on the boot in order to remove the wire from the ignition coil.

8. Remove the oil level indicator tube from the engine block. Refer to Oil Level Indicator and Tube Replacement .



9. Remove the exhaust manifold bolts and exhaust manifold.
10. Remove and discard the exhaust manifold gasket.
11. Remove and discard the exhaust manifold seal.



12. If replacing the exhaust manifold, remove the exhaust manifold heat shield bolts, and shield from the exhaust manifold.

Important: 

Notice: Refer to Fastener Notice in the Preface section.




1. If the exhaust manifold was replaced, position and install the exhaust manifold heat shield, and bolts to the exhaust manifold.

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




2. Clean the threads of the exhaust manifold bolts.
3. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
4. Install a NEW catalytic converter seal to the exhaust manifold.
5. Position the NEW exhaust manifold gasket and exhaust manifold to the cylinder head.
6. Ensure that the catalytic converter seal is seated to the catalytic converter.
7. Install the exhaust manifold bolts.

Tighten

1. Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
2. Tighten the bolts a final pass to 20 N·m (15 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
8. Using a flat punch, bend the gasket tab at the rear of the gasket around the cylinder head edge.
9. Install the oil level indicator tube to the engine block. Refer to Oil Level Indicator and Tube Replacement .



10. Install the spark plug wires (1) to the spark plugs.
11. Install the spark plug wires to the ignition coils.
12. Inspect the spark plug wires for proper installation.

12.1.

Push sideways on each boot in order to inspect the seating.

12.2.

Reinstall any loose boot.

13. Fully raise and support the vehicle.



14. Install the catalytic converter to exhaust manifold nuts. (1500 series shown, 2500 series similar).

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

15. Partially lower the vehicle in order to work through the wheel opening.
16. Install the front wheel house liner - right front. Refer to Front Wheelhouse Liner Replacement - Right Side .
17. Install the HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .
18. Inspect the exhaust system for leaks.