No need for a torch, but you will need to remove the exhaust system from the catalyst flanges back. On the manifolds there are heat shields that are held in place with 10mm bolts, at least three. The heat shield does not necessarily need to be removed from the engine compartment, as just positioning aside to access the upper converter to manifold stud/nuts will do. The converter studs will be accessed from the top side, and they are either 15mm or 18mm. The left side may require steering shaft removal as well. You may want to check with your dealer, as this may be covered under emissions warranty, and they can replace it for you. I have included the procedure from GM service info, it is a bit different, but I do them more as I described above. This is all assuming that it is a 3.6(LY7) engine and not a 4.6 V8. If it is a 4.6 there is a special coverage adjustment to your manufacturers warranty the covers replacement.
Catalytic Converter Replacement - Left Side (LY7)
Caution: Refer to Exhaust Service Caution in the Preface section.
Caution: Refer to Protective Goggles and Glove Caution in the Preface section.
Remove the left bank exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side.
Remove the catalytic converter nuts.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Disconnect the oxygen sensor electrical connector.
Disconnect the muffler pipe from the left and right side catalytic converters.
Remove the exhaust pipe to right bank catalytic converter fasteners.
Carefully remove the catalytic converter with the seal/heat shield and oxygen sensor from the exhaust manifold. Remove and discard the catalytic converter inlet seal/heat shield from the converter assembly. Do not reuse.
Remove the oxygen sensor from the catalytic converter. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1.
Install the oxygen sensor to the catalytic converter. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1.
Important: Do not reuse the catalytic converter inlet seal/heat shield. Always replace with new.
Install the NEW catalytic converter seal/heat shield to the catalytic converter.
Carefully install the catalytic converter to the exhaust manifold.
Install the catalytic converter nuts.
Connect the oxygen sensor electrical connector.
Notice: Refer to Fastener Notice in the Preface section.
Important: Inspect the catalytic converter seals. Replace the seals if they are worn or damaged.
Connect the muffler pipes to the left and right side catalytic converters.
Tighten the muffler nuts to 22 N m (16 lb ft).
Lower the vehicle.
Tighten the catalytic converter to exhaust manifold fasteners.
Tighten the catalytic converter nuts to 50 N m (37 lb ft).
Install the right bank exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side.
Wednesday, May 25th, 2011 AT 6:49 PM