Exhaust Manifold Replacement - Left Side

Exhaust Manifold Replacement - Left Side (LS3) (6.2L)

Removal Procedure

1. Remove the engine sight cover. Refer to Upper Intake Manifold Sight Shield Replacement (LS9) (Service and Repair)Upper Intake Manifold Sight Shield Replacement (w/o LS9) (Service and Repair).
2. Remove the generator. Refer to Generator Replacement (LS3 or LS7) (Generator Replacement)Generator Replacement (LS9) (Generator Replacement).
3. Remove the bank 1, sensor 1 oxygen sensor from the exhaust manifold. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (Service and Repair).
4. Remove the spark plugs. Refer to Spark Plug Replacement (Service and Repair).




5. Remove the catalytic convertor. Refer to Catalytic Converter Replacement - Left Side (7.0L) (Catalytic Converter Replacement - Left Side (7.0L)).
6. Remove the exhaust manifold bolts.

Note: It may be necessary to remove the heat assembly from the exhaust manifold to gain enough clearance to remove the exhaust manifold.

7. Remove the exhaust manifold.

Installation Procedure

Note: The cylinder head exhaust manifold bolt hole threads must be cleaned and free of debris or threadlocking material.

Note: In the following service procedure, position the catalytic convertor on the intermediate pipe, but DO NOT tighten the clamp. Leave it loose to allow the alignment of the exhaust manifold on the cylinder head.

1. Install the catalytic convertor.
2. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953489), or equivalent to the threads of the exhaust manifold bolts.




3. Position the exhaust manifold and a NEW gasket into place.

Caution: Refer to Fastener Caution (Fastener Caution).

4. Install the exhaust manifold bolts using the following sequence:

Note: Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, working toward the outside bolts.

1. Tighten the exhaust manifold bolts a first pass to 15 Nm (11 lb ft).

Note: Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, working toward the outside bolts.

2. Tighten the exhaust manifold bolts a final pass to 25 Nm (18 lb ft).

5. Install the bank 1, sensor 1 oxygen sensor in the exhaust manifold oxygen sensor. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (Service and Repair).
6. Install the spark plugs. Refer to Spark Plug Replacement (Service and Repair).
7. Install the generator. Refer to Generator Replacement (LS3 or LS7) (Generator Replacement)Generator Replacement (LS9) (Generator Replacement).
8. Install the engine sight cover. Refer to Upper Intake Manifold Sight Shield Replacement (LS9) (Service and Repair)Upper Intake Manifold Sight Shield Replacement (w/o LS9) (Service and Repair).
9. Install the catalytic convertor. Refer to Catalytic Converter Replacement - Left Side (7.0L) (Catalytic Converter Replacement - Left Side (7.0L)).