GM Service Manual Online
For 1990-2009 cars only

Exhaust Manifold Replacement - Left Side LX9

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure


    Object Number: 1523734  Size: SH
  1. Remove the air intake duct. Refer to Air Cleaner Inlet Duct Replacement .
  2. Remove the connector position assurance (CPA) retainer (2).
  3. Disconnect the heated oxygen sensor (HO2S) electrical connector (1).
  4. 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. Object Number: 1523736  Size: SH
  7. Remove the exhaust manifold heat shield bolts and shield.

  8. Object Number: 1523737  Size: SH
  9. Remove the upper exhaust manifold nuts.
  10. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  11. Remove the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .
  12. Remove the lower exhaust manifold nuts.
  13. Remove the exhaust manifold.
  14. Remove and discard the exhaust manifold gasket.

Installation Procedure


    Object Number: 1523737  Size: SH
  1. Install a NEW exhaust manifold gasket onto the cylinder head studs.
  2. Install the exhaust manifold.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the exhaust manifold nuts.
  5. Tighten
    Tighten the nuts to 16 N·m (12 lb ft).

  6. Install the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .

  7. Object Number: 1523736  Size: SH
  8. Install the exhaust manifold heat shield and bolts.
  9. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1523735  Size: SH

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

  10. Install the HO2S using J 39194-B .
  11. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).

  12. Connect the HO2S electrical connector (1).
  13. Install the CPA retainer (2).
  14. Ensure that the connector rosebud is attached to the clip.
  15. Install the air intake duct. Refer to Air Cleaner Inlet Duct Replacement .

Exhaust Manifold Replacement - Left Side LZ9

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure


    Object Number: 1581869  Size: SH
  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.

  5. Object Number: 1585918  Size: SH

    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.

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

  7. Object Number: 1585276  Size: SH
  8. Remove the exhaust manifold heat shield bolts.
  9. Remove the exhaust manifold heat shield.

  10. Object Number: 1585278  Size: SH
  11. Remove the upper exhaust manifold bolts.
  12. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  13. Remove the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .
  14. Remove the lower exhaust manifold bolts.
  15. Remove the exhaust manifold.
  16. Remove and discard the exhaust manifold gasket.

Installation Procedure


    Object Number: 1585278  Size: SH
  1. Install a NEW exhaust manifold gasket onto the cylinder head studs.
  2. Install the exhaust manifold.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the exhaust manifold bolts.
  5. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

  6. Install the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side .
  7. Lower the vehicle.

  8. Object Number: 1585276  Size: SH
  9. Install the exhaust manifold heat shield.
  10. Install the exhaust manifold heat shield bolts.
  11. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1585918  Size: SH

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

  12. Install the HO2S using J 39194-B .
  13. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1581869  Size: SH
  14. Connect the HO2S electrical connector (1).
  15. Install the CPA retainer (2).
  16. Install the HO2S clip (3) to the oil level indicator tube bracket.
  17. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .