Exhaust Manifold Replacement - Left Side LX9

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

1. Remove the air intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.5L (LX9).
2. Remove the connector position assurance (CPA) retainer (2).
3. Disconnect the heated oxygen sensor (HO2S) electrical connector (1).

Important: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

4. Remove the HO2S using the J 39194-B .



5. Remove the exhaust manifold heat shield bolts and shield.
6. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 3.5L (LX9).
7. Remove the front catalytic converter. Refer to Catalytic Converter Replacement .



8. Lower the vehicle.
9. Remove the exhaust manifold nuts.
10. Remove the exhaust manifold.
11. Remove and discard the exhaust manifold gasket.

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

Notice: Refer to Fastener Notice in the Preface section.

3. Install the exhaust manifold nuts.

Tighten
Tighten the nuts to 16 N·m (12 lb ft).

4. Install the front catalytic converter. Refer to Catalytic Converter Replacement .
5. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls -  3.5L (LX9).



6. Install the exhaust manifold heat shield and bolts.

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





Important: Whenever the oxygen sensor is removed, coat the threads with nickel-based anti-seize compound, such as GM P/N 5613695, or equivalent.

7. Install the HO2S using J 39194-B .

Tighten
Tighten the sensor to 42 N·m (31 lb ft).

8. Connect the HO2S electrical connector (2).
9. Install the CPA retainer (1).
10. Install the air intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.5L (LX9).

Exhaust Manifold Replacement - Left Side LZ9

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

1. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
2. Remove the connector position assurance (CPA) retainer (5).
3. Disconnect the heated oxygen sensor (HO2S) electrical connector (4).
4. Remove the HO2S clip (3) from the oil level indicator tube bracket.




Important: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

5. Remove the HO2S using the J 39194-B .



6. Remove the exhaust manifold heat shield bolts.
7. Remove the exhaust manifold heat shield.



8. Remove the upper exhaust manifold bolts.
9. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
10. Remove the front catalytic converter. Refer to Catalytic Converter Replacement .
11. Remove the lower exhaust manifold bolts.
12. Remove the exhaust manifold.
13. Remove and discard the exhaust manifold gasket.

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

Notice: Refer to Fastener Notice in the Preface section.

3. Install the exhaust manifold bolts.

Tighten
Tighten the bolts to 20 N·m (15 lb ft).

4. Install the front catalytic converter. Refer to Catalytic Converter Replacement .
5. Lower the vehicle.



6. Install the exhaust manifold heat shield.
7. Install the exhaust manifold heat shield bolts.

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





Important: Whenever the oxygen sensor is removed, coat the threads with nickel-based anti-seize compound, such as GM P/N 5613695, or equivalent.

8. Install the HO2S using J 39194-B .

Tighten
Tighten the sensor to 42 N·m (31 lb ft).




9. Connect the HO2S electrical connector (1).
10. Install the CPA retainer (2).
11. Install the HO2S clip (3) to the oil level indicator tube bracket.
12. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .