Exhaust Manifold Replacement - Left Side LH8

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Remove the catalytic converter to exhaust manifold nuts (2).
3. Lower the vehicle.
4. Remove the upper intake manifold sight shield. Refer to Upper Intake Manifold Sight Shield Replacement
5. Remove the spark plugs. Refer to Spark Plug Replacement .
6. Disconnect the ignition coil bracket from the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Left Side
7. Remove the exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side .



8. Remove the exhaust manifold bolts (1).
9. Remove the exhaust manifold (2) and gasket (3). Discard the gasket.

Important: 

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

1. 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.
2. Ensure that the exhaust seal is still seated on the catalytic converter recess.
3. Install one exhaust manifold bolt to the exhaust manifold (2) and place the NEW gasket (3) onto the bolt.
4. Install the exhaust manifold to the catalytic converter flange and position the manifold to the cylinder head.

Notice: Refer to Fastener Notice in the Preface section.

5. Install the remaining exhaust manifold bolts (1).

Tighten

1. Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the 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 25 N·m (18 lb ft). Tighten the 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 exhaust manifold gasket at the rear of the left cylinder head.
7. Install the exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side .
8. Install the ignition coil bracket to the valve rocker arm cover. refer to Valve Rocker Arm Cover Replacement - Left Side
9. Install the spark plugs. Refer to Spark Plug Replacement .
10. Install upper intake manifold sight shield. Refer to Upper Intake Manifold Sight Shield Replacement
11. Raise the vehicle.



12. Install the catalytic converter to exhaust manifold nuts (2).

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

13. Lower the vehicle.