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Home >> Chevrolet >> 2004 >> Impala SS >> Repair and Diagnosis >> Engine Mechanical >> Engine Exhaust System >> Repair Instructions >> Catalytic Converter Replacement (3.4L) >> Installation Procedure

Installation Procedure

  1. Install the heated oxygen sensor (HO2S) to the catalytic converter. Refer to Heated Oxygen Sensor Replacement - Position 2 in Engine Controls - 3.4L.
  2. Fig 1: Installing HO2S To Catalytic Converter (3.4L)
    GM372612Courtesy of GENERAL MOTORS CORP.
    NOTE: 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.
  3. Install a new gasket to the exhaust pipe studs.
  4. Install a new exhaust manifold pipe gasket.
  5. NOTE: Refer to Catalytic Converter Movement Notice in Cautions and Notices.
  6. Install and support the 3-way catalytic converter.
  7. Install the catalytic converter nuts.
  8. Fig 2: View Of Catalytic Converter Mounting Nuts
    GM212193Courtesy of GENERAL MOTORS CORP.
    NOTE: Refer to Fastener Notice in Cautions and Notices.
  9. Install the exhaust manifold pipe stud nuts.

    Tighten: 

    • Tighten the exhaust manifold pipe stud nuts to 35 N.m (26 lb ft).
    • Tighten the catalytic converter nuts to 60 N.m (44 lb ft).

  10. Fig 3: Installing Exhaust Manifold Pipe Stud Nuts (3.4L)
    GM260064Courtesy of GENERAL MOTORS CORP.
  11. Install the catalytic converter hangers.
  12. Fig 4: View Of Catalytic Converter Hangers
    GM289493Courtesy of GENERAL MOTORS CORP.
  13. Connect the heated oxygen sensor (HO2S) electrical connector.
  14. Lower the vehicle.
  15. Inspect the exhaust system for leaks.