Exhaust Manifold Replacement - Left Side 6.6L

Exhaust Manifold Replacement - Left Side 4.3L

1. Remove the left front wheel and tire. Refer to Tire and Wheel Removal and Installation .
2. Remove the left wheelhouse splash shield. Refer to Wheelhouse Splash Shield Replacement .
3. Remove the catalytic converter assembly. Refer to Catalytic Converter Replacement .
4. Remove the spark plugs. Refer to Spark Plug Replacement .
5. Remove the exhaust manifold bolts (3) and stud (4).
6. Remove the exhaust manifold (2) .
7. Remove and discard the exhaust manifold gaskets (1).

Important: To aid in installing the exhaust manifold to the engine, the bolt holes on the NEW exhaust manifold gaskets have tabs that will hold the gasket and the bolts in place.

1. Install the exhaust manifold bolts (3) and stud (4) to the manifold.
2. Install NEW exhaust manifold gaskets (1) onto the bolt and stud.

Notice: Refer to Fastener Notice in the Preface section.

3. Position and install the exhaust manifold (2) to the cylinder head.

Tighten

1. Tighten the bolts/stud a first pass to 15 N·m (11 lb ft).
2. Tighten the bolts/stud a final pass to 30 N·m (22 lb ft).
4. Install the spark plugs. Refer to Spark Plug Replacement .
5. Install the catalytic converter assembly. Refer to Catalytic Converter Replacement .
6. Install the left wheelhouse splash shield. Refer to Wheelhouse Splash Shield Replacement .
7. Install the left front wheel and tire. Refer to Tire and Wheel Removal and Installation .

Exhaust Manifold Replacement - Left Side 4.8L/5.3L/6.0L

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .



2. Separate the catalytic converter from the exhaust manifold. Refer to Catalytic Converter Replacement .
3. Lower the vehicle.
4. Remove the engine cover. Refer to Engine Cover Replacement .
5. Disconnect the exhaust gas recirculation (EGR) pipe from the exhaust manifold, if equipped.
6. Remove the spark plug wires from the spark plugs. Refer to Spark Plug Wire Replacement .
7. Remove the exhaust manifold bolts and remove the exhaust manifold from the vehicle.
8. Discard the gasket and the exhaust manifold to catalytic converter seal.



9. Remove the heat shield (603) and bolts (604) from the manifold (600), as required.
10. Remove the studs (605), as required.

Notice: Refer to Fastener Notice in the Preface section.





Important: 

•	Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or on-board diagnostic (OBD) II system performance.

•	The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.

•	Do not apply sealant to the first 3 threads of the bolt.

1. Install the heat shield (603) and bolts (604).

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

2. Install the exhaust pipe studs (605).

Tighten
Tighten the studs to 20 N·m (15 lb ft).




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. Refer to Adhesives, Fluids, Lubricants, and Sealers .
4. Position the exhaust manifold gasket to the manifold with two manifold bolts.
5. Install the exhaust manifold to the cylinder head.

Tighten

1. Tighten the manifold bolts a first pass to 15 N·m (11 lb ft). Tighten the manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
2. Tighten the manifold bolts a final pass to 20 N·m (15 lb ft). Tighten the manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
6. Using a flat punch, bend over the exposed edge of the manifold gasket at the rear of the cylinder head.
7. Connect the EGR pipe to the manifold, if equipped.
8. Install the spark plug wires to the spark plugs. Refer to Spark Plug Wire Replacement .
9. Using a NEW seal, install the catalytic converter to the exhaust manifold. Refer to Catalytic Converter Replacement .
10. Install the engine cover. Refer to Engine Cover Replacement .
11. Inspect for exhaust leaks.