Exhaust Manifold Replacement - Left Side LZ4

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

Notice: The use of excessive force may damage the threads in the exhaust manifold/pipe.

Important: The in-line connector and louvered end must be kept clear of grease, dirt or other contaminants. Avoid using cleaning solvents of any type. DO NOT drop or roughly handle the heated oxygen sensor (HO2S).

Important: The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F)

1. Remove the air intake duct. Refer to Air Cleaner Inlet Duct Replacement .
2. Remove the connector position assurance (CPA) retainer (5).
3. Disconnect the engine wiring harness electrical connector (4) from the HO2S electrical connector (3).
4. Remove the HO2S electrical connector rosebud clip from the oil level indicator tube tab.



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



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



7. Remove the upper exhaust manifold bolts.
8. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
9. Remove the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .
10. Remove the lower exhaust manifold bolts.
11. Remove the exhaust manifold.
12. 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 left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .
5. Lower the vehicle.



6. Install the exhaust manifold heat shield and bolts.

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





Important: A special anti-seize compound is used on the HO2S threads. The compound consists of graphite suspended in fluid and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine and is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.

7. Coat the threads of the HO2S with anti-seize compound GM P/N 12377953 or equivalent, if necessary.
8. Install the HO2S using J 39194-B .

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

9. Connect the engine wiring harness electrical connector (4) to the HO2S electrical connector (3).
10. Install the HO2S electrical connector rosebud clip to the oil level indicator tube tab.
11. Install the CPA retainer (5).
12. Install the air intake duct. Refer to Air Cleaner Inlet Duct Replacement .