GM Service Manual Online
For 1990-2009 cars only

Front Pipe Replacement 2.5L

Removal Procedure

  1. Disconnect the Heated Oxygen Sensor (HO2S1) electrical connectors and detach the couplers from the coupler mounting bracket.
  2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Remove the propeller shaft. Refer to Front Propeller Shaft Replacement .

  4. Object Number: 713062  Size: SH
  5. Remove the 2 bolts (1) from the front pipe assembly (2).

  6. Object Number: 713065  Size: SH
  7. Remove the 6 front pipe nuts (1) from the exhaust manifolds (2).
  8. Remove the front pipe and the exhaust manifold gaskets.

Installation Procedure

    Important: When installing a new exhaust system component, always use new gaskets and seals.

  1. Position the front pipe with new exhaust manifold gaskets.

  2. Object Number: 713065  Size: SH
  3. Install the 6 front pipe nuts (1) to the exhaust manifolds (2). Do not fully tighten the nuts.

  4. Object Number: 713062  Size: SH
  5. Install the 2 bolts (1) to the front pipe assembly (2). Do not fully tighten the bolts.
  6. Install the propeller shaft. Refer to Front Propeller Shaft Replacement .
  7. Align all system components before tightening the fasteners, in order to prevent noise or vibrations.
  8. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  9. Tighten the front pipe assembly bolts.
  10. Tighten
    Tighten the front pipe assembly bolts to 50 N·m (37 lb ft).

  11. Tighten the front pipe assembly nuts.
  12. Tighten
    Tighten the front pipe assembly nuts to 50 N·m (37 lb ft).

  13. Lower the vehicle.
  14. Connect the Heated Oxygen Sensor (HO2S1) electrical connectors and attach the couplers to the coupler mounting bracket.

Front Pipe Replacement 2.0L

Removal Procedure

  1. On California 2.0L engine, remove 5 upper exhaust manifold heat shield bolts.
  2. Remove the upper exhaust manifold heat shield.

  3. Object Number: 1178073  Size: SH
  4. Remove 3 exhaust manifold to front pipe nuts (1).
  5. On all, raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  6. On California 2.0L engine, remove the heated oxygen sensor (HO2S) 2. Refer to Heated Oxygen Sensor 2 Replacement in Engine Controls-2.0L.

  7. Object Number: 1178081  Size: SH
  8. Remove 1 bolt and 1 nut from the exhaust manifold pipe bracket.

  9. Object Number: 185746  Size: SH
  10. On all, remove 2 bolts and the front pipe/TWC assembly (2) from the exhaust manifold (1).

  11. Object Number: 492870  Size: MH
  12. On non-California 2.0L engine, remove the electrical connector at the heated oxygen sensor (H02S2) (6).

  13. Object Number: 166026  Size: SH
  14. On all, remove two nuts and the front pipe/TWC assembly (1) from the resonator/muffler/tail pipe assembly.
  15. Remove the hanger supporting the TWC.
  16. Remove the front pipe/TWC assembly (1) from the vehicle.
  17. Clean the gasket and the seal mating surfaces.

Installation Procedure

Important: When installing a new exhaust system component, always use new gaskets and seals.

  1. On all, install the front pipe/TWC assembly to the vehicle.
  2. Support the TWC with a hanger.
  3. Attach the front pipe/TWC assembly with a new gasket to the resonator/muffler/tail pipe assembly.
  4. Secure the resonator/muffler/tail pipe assembly with 2 nuts. Do not fully tighten the nuts.

  5. Object Number: 492870  Size: MH
  6. On non-California 2.0L engine, attach the electrical connector to the heated oxygen sensor (H02S2) (6).
  7. On all, connect the front pipe/TWC assembly, with a new seal, to the exhaust manifold and secure with 2 bolts. Do not fully tighten the bolts.
  8. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1178081  Size: SH
  9. On California 2.0L engine, install 1 bolt and 1 nut to the exhaust manifold pipe bracket.
  10. Tighten
    Tighten the front exhaust pipe bracket nut and bolt to 50 N·m (37 lb ft).

  11. Install the heated oxygen sensor (HO2S) 2. Refer to Heated Oxygen Sensor 2 Replacement in Engine Controls-2.0L.
  12. On non-California engines, align all system components before tightening the fasteners, in order to prevent noise or vibrations.
  13. Tighten

        • Tighten the front pipe/TWC assembly-to-exhaust manifold bolts to 50 N·m (37 lb ft).
        • Tighten the front pipe/TWC assembly-to-resonator/muffler/tail pipe assembly nuts to 35 N·m (26 lb ft).
  14. On California 2.0L engine, align all system components before tightening the fasteners, in order to prevent noise or vibrations.
  15. Tighten
    Tighten the front pipe/TWC assembly-to-resonator/muffler/tail pipe assembly nuts to 35 N·m (26 lb ft).

  16. On all, lower the vehicle.

  17. Object Number: 1178073  Size: SH
  18. On California 2.0L engine, install 3 exhaust manifold to front pipe nuts (1).
  19. Tighten
    Tighten the front pipe assembly-to-exhaust manifold bolts to 50 N·m (37 lb ft).

  20. Position exhaust manifold upper heat shield to the exhaust manifold.
  21. Install 5 exhaust manifold upper heat shield bolts.