Exhaust Manifold: Service and Repair

Exhaust Manifold Replacement (LL8) (4.2L)

Removal Procedure





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 exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement (LL8) (Exhaust Manifold Heat Shield Replacement) .




5. Remove the exhaust manifold bolts.
6. Remove the exhaust manifold.




7. Remove the exhaust manifold gasket.



Installation Procedure





1. Position a NEW exhaust manifold gasket to the cylinder head.




2. Position the exhaust manifold to the cylinder head and install the studs to the catalytic converter.
3. Apply threadlock GM P/N 12345493 (Canadian P/N 10953488) to the exhaust manifold bolt threads.
4. Install the exhaust manifold bolts.





Notice: Refer to Fastener Notice .

5. Tighten the exhaust manifold bolts in the sequence shown.

1. Tighten the bolts first pass in sequence to 20 N.m (15 lb ft).
2. Tighten the bolts second pass in sequence to 20 N.m (15 lb ft).
3. Tighten the bolts final pass in sequence to 20 N.m (15 lb ft).






6. Install the exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement (LL8) (Exhaust Manifold Heat Shield Replacement) .
7. Raise the suitably support the vehicle.
8. Install the catalytic converter to exhaust manifold nuts (2).

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

9. Lower the vehicle.