Caution: Refer to Exhaust Service Caution in the Preface section.

Caution: Refer to Protective Goggles and Glove Caution in the Preface section.

1. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 3.5L (L52).
2. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls - 3.5L (L52).
3. If equipped with an automatic transmission, remove the transmission filler tube bracket nut from the secondary air injection (A.I.R.) adapter, and position aside.
4. Remove the heated oxygen sensor (HO2S) from the exhaust manifold. Refer to Heated Oxygen Sensor 1 Replacement in Engine Controls - 3.5L (L52).



5. Remove the nuts securing the heat shield to the exhaust manifold.
6. Remove the exhaust manifold heat shield.

1. Install the exhaust manifold heat shield to the exhaust manifold.
2. Apply anti-seize GM P/N 12371386 (Canadian P/N 993128) to the exhaust manifold heat shield nuts.

Notice: Refer to Fastener Notice in the Preface section.

3. Install the exhaust manifold heat shield nuts.

Tighten
Tighten the nuts to 10 N·m (89 lb in).

4. Install the HO2S to the exhaust manifold. Refer to Heated Oxygen Sensor 1 Replacement in Engine Controls - 3.5L (L52).



5. Position the automatic transmission filler tube to the A.I.R. adapter if previously removed.
6. Install the automatic transmission filler tube bracket nut.

Tighten
Tighten the nut to 12.5 N·m (111 lb in).

7. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls - 3.5L (L52).
8. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 3.5L (L52).