GM Service Manual Online
For 1990-2009 cars only

Exhaust Seal Replacement With L9H, LY2, LY5 or LFA

Removal Procedure

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

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

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the oil pan skid plate , if equipped. Refer to Oil Pan Skid Plate Replacement.

  3. Object Number: 1704008  Size: SH
  4. Remove heated oxygen (HO2S) (1, 2 and 3) and disconnect the heated oxygen (HO2S) sensors (4 and 5) harness connectors.
  5. • For the L9H, LY2, or LY5 engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.
    • For the LFA engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2

    Object Number: 1708626  Size: SH
  6. Remove the catalytic converter pipe to the exhaust manifold nuts (1) and lower the converter.
  7. Remove the exhaust seals (2 and 3) and discard.

Installation Procedure


    Object Number: 1708626  Size: SH
  1. Install NEW exhaust manifold seals (2 and 3).
  2. Install the catalytic converter pipe to the exhaust manifolds.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the catalytic converter pipe to exhaust manifold nuts (1) and tighten to 50 N·m (37 lb ft).
  5. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement.

  6. Object Number: 1704008  Size: SH
  7. Inatall heated oxygen (HO2S) (1, 2 and 3) and connect the heated oxygen (HO2S) sensors (4 and 5) harness connectors.
  8. • For the L9H, LY2, or LY5 engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.
    • For the LFA engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2
  9. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement.
  10. Install the oil pan skid plate if equipped. Refer to Oil Pan Skid Plate Replacement.
  11. Lower the vehicle.
  12. Inspect for exhaust leaks.

Exhaust Seal Replacement With L92

Removal Procedure

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

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

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the oil pan skid plate , if equipped. Refer to Oil Pan Skid Plate Replacement.

  3. Object Number: 1704008  Size: SH
  4. Disconnect the heated oxygen (HO2S) sensors harness connectors. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.

  5. Object Number: 1708626  Size: SH
  6. Remove the catalytic converter pipe to the exhaust manifold nuts (1).
  7. Remove the exhaust seals (2 and 3) and discard.

Installation Procedure


    Object Number: 1708626  Size: SH
  1. Install NEW exhaust manifold seals (2 and 3).
  2. Install the catalytic converter pipe to the exhaust manifolds.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the catalytic converter pipe to exhaust manifold nuts (1) and tighten to 50 N·m (37 lb ft).
  5. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement.

  6. Object Number: 1704008  Size: SH
  7. Connect the heated oxygen (HO2S) sensors harness connectors. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.
  8. Install the oil pan skid plate if equipped. Refer to Oil Pan Skid Plate Replacement.
  9. Lower the vehicle.
  10. Inspect for exhaust leaks.