Exhaust Manifold Replacement - Left Side LD8

1. Remove the front engine mount bracket. Refer to Engine Front Mount Bracket Replacement.
2. Remove the connector position assurance (CPA) retainer.
3. Disconnect the engine harness electrical connector (3) from the heated oxygen sensor (HO2S).



4. Remove the HO2S.



5. Remove the exhaust manifold front pipe bolts (2).



6. Remove the exhaust manifold bolts.
7. Remove the exhaust manifold (2).
8. Remove and discard the exhaust manifold gasket (1).
9. Remove and discard the front exhaust manifold pipe seal.
10. Remove the front exhaust manifold pipe flange.

1. Install the front exhaust manifold pipe flange and a NEW seal onto the exhaust manifold.
2. Insert the upper right exhaust manifold bolt to the manifold in this location (2).
3. Place the NEW exhaust manifold gasket over the bolt and against the manifold.
4. Insert the exhaust manifold into the front exhaust manifold pipe and against the cylinder head.
5. Finger start the exhaust manifold bolt.

Caution: Refer to Fastener Caution in the Preface section.

6. Install the remaining exhaust manifold bolts and tighten all exhaust manifold bolts starting from right to left beginning with the bolt in this location (2). Tighten the bolts 25 N·m (18 lb ft)



7. Install the exhaust manifold front pipe bolts (2).



8. If reusing the old HO2S, coat the threads with anti-sieze compound, GM P/N 12377953 or equivalent.
9. Install the HO2S and tighten to 41 N·m (30 lb ft).



10. Connect the engine harness electrical connector  (3) to the HO2S.
11. Install the CPA retainer.
12. Install the front engine mount bracket. Refer to Engine Front Mount Bracket Replacement.

Exhaust Manifold Replacement - Left Side LZ9 or LGD

1. Remove the air cleaner outler duct. Refer to Air Cleaner Outlet Duct Replacement.



2. Remove the exhaust crossover pipe heat shield bolts.
3. Remove the exhaust crossover pipe heat shield.



4. Remove the exhaust manifold heat shield bolts.
5. Remove the exhaust manifold heat shield.



6. Remove the exhaust crossover pipe to left exhaust manifold nuts.



7. Remove the exhaust manifold bolts.
8. Remove the exhaust manifold bolts.
9. Remove the exhaust manifold.
10. Remove and discard the exhaust manifold gasket.

1. Install a NEW exhaust manifold gasket onto the cylinder head studs.
2. Install the exhaust manifold.

Caution: Refer to Fastener Caution in the Preface section.

3. Install the exhaust manifold bolts and tighten to 20 N·m (15 lb ft).



4. Install the exhaust crossover pipe to left exhaust manifold nuts and tighten to 20 N·m (15 lb ft).



5. Install the exhaust manifold heat shield.
6. Install the exhaust manifold heat shield bolts and tighten to 10 N·m (89 lb in).
7. Install the engine front mount bracket. Refer to Engine Front Mount Bracket Replacement.



8. Install the exhaust crossover pipe heat shield.
9. Install the exhaust crossover pipe heat shield bolts and tighten to 10 N·m (89 lb in).
10. Install the air cleaner outler duct. Refer to Air Cleaner Outlet Duct Replacement.