GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement LLR

Removal Procedure

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

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


    Object Number: 1363915  Size: SH
  1. Remove the right torsion bar. Refer to Torsion Bar Replacement.
  2. Disconnect the heated oxygen sensor (HO2S) at the sensor pigtail (3).
  3. Remove the HO2S if replacement is necessary. Refer to Heated Oxygen Sensor 2 Replacement.

  4. Object Number: 1560120  Size: MH

    Note: Do not use oil base lubricants.

  5. Apply a soapy solution to the exhaust muffler hanger rod (3) in order to ease the removal of the exhaust hanger (2), if necessary.
  6. Pry the exhaust hanger (2) free from the exhaust muffler hanger rod (3), if necessary.

  7. Object Number: 1560112  Size: SH
  8. Remove the nuts securing the muffler to the catalytic converter.
  9. Position the muffler rearward enough to allow the studs located in the muffler to clear the catalytic converter pipe flange.

  10. Object Number: 1313621  Size: SH
  11. Remove the nuts attaching the catalytic converter to the exhaust manifold.
  12. Remove the catalytic converter.

  13. Object Number: 1313620  Size: SH
  14. Remove and discard the exhaust manifold seal at the exhaust manifold flange.

Installation Procedure


    Object Number: 1313620  Size: SH
  1. Install a NEW seal to the exhaust manifold flange.
  2. Caution: Refer to Exhaust System Inspection Caution in the Preface section.


    Object Number: 1313621  Size: SH
  3. Install the catalytic converter to the exhaust manifold.
  4. Install the nuts attaching the catalytic converter to the exhaust manifold. Do not tighten at this time.

  5. Object Number: 1560112  Size: SH
  6. Align the catalytic converter with the studs located in the muffler.
  7. Caution: Refer to Fastener Caution in the Preface section.

  8. Install the nuts securing the muffler to the catalytic converter. Tighten the nuts by hand until each contacts the metal flange.
  9. Tighten
    Tighten the nuts to 45 N·m (33 lb ft).

  10. Tighten the catalytic converter nuts previously installed in step 3.
  11. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).

  12. Install the HO2S if previously removed. Refer to Heated Oxygen Sensor 2 Replacement.

  13. Object Number: 1560120  Size: MH

    Note: Do not use oil base lubricants.

  14. Apply a soapy solution to the following in order to ease the installation of the hanger (2):
  15. • The inner diameter of the exhaust muffler hanger (2)
    • The exhaust muffler hanger rod (3)

    Object Number: 1363915  Size: SH
  16. Connect the HO2S at the pigtail (3).
  17. Install the right torsion bar. Refer to Torsion Bar Replacement.