GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 LaCrosse 🢒 Engine 🢒 Engine Controls and Fuel - 3.6L 🢒 Catalytic Converter Replacement

Removal Procedure

    Object Number: 911163 Size: SH

    Important: The catalytic converter is serviced by replacing the entire assembly. Always replace the gaskets at the front and rear flanges when servicing the catalytic converter. Never install the original gasket.

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Disconnect the heated oxygen sensor (HO2S) electrical connector.
  3. Remove the exhaust manifold pipe stud nuts (2).
  4. Remove the exhaust manifold pipe gasket (1).
  5. Support the exhaust system.

    6. Object Number: 212193 Size: SH
  6. Remove the catalytic converter nuts.

    7. Object Number: 289493 Size: SH
  7. Remove the catalytic converter hangers.
  8. Remove the catalytic converter.
  9. Remove the catalytic converter gasket.
  10. Clean and inspect the exhaust manifold and the exhaust pipe gasket mating surfaces.
  11. Remove the HO2S. Refer to Heated Oxygen Sensor 2 Replacement .

Installation Procedure

    Object Number: 212193 Size: SH
  1. Install the HO2S. Refer to Heated Oxygen Sensor 2 Replacement .

    2. Notice: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.

  2. Install a new gasket to the exhaust pipe studs.
  3. Install and support the catalytic converter.

    4. 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.

  4. Install the catalytic converter nuts.

    5. Tighten
    Tighten the nuts to 60 N·m (44 lb ft).


    Object Number: 911163 Size: SH
  5. Install a new exhaust manifold pipe gasket (1).
  6. Install the exhaust manifold pipe stud nuts (2).

    7. Tighten
    Tighten the nuts to 35 N·m (26 lb ft).


    Object Number: 289493 Size: SH
  7. Install the catalytic converter hangers.
  8. Remove the support from the exhaust system.
  9. Connect the HO2S electrical connector.
  10. Inspect the exhaust system for leaks and underbody contact.
  11. Lower the vehicle.