Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSPONTIAC2008GRAND PRIX BASEREPAIR AND DIAGNOSISENGINE MECHANICALENGINE EXHAUST SYSTEMREPAIR INSTRUCTIONSCATALYTIC CONVERTER REPLACEMENT (L26)INSTALLATION PROCEDURE

2008 Pontiac Grand Prix Base

Installation Procedure

2008 Pontiac Grand Prix BaseSECTION Installation Procedure

Fig 1: View Of Catalytic Converter Mounting Nuts

Courtesy of GENERAL MOTORS CORP.

Install the HO2S. Refer to Heated Oxygen Sensor 2 Replacement .

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.

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

NOTE: Refer to FASTENER NOTICE .

Install the catalytic converter nuts.
Tighten: Tighten the nuts to 60 N.m (44 lb ft).

Fig 2: Right Exhaust Manifold & Catalytic Converter Pipe

Courtesy of GENERAL MOTORS CORP.

Install a new catalytic converter pipe gasket (1).
Install the catalytic converter pipe stud nuts (2).
Tighten: Tighten the nuts to 35 N.m (26 lb ft).

Fig 3: View Of Catalytic Converter Hangers

Courtesy of GENERAL MOTORS CORP.

Install the catalytic converter hangers.
Remove the support from the exhaust system.
Connect the HO2S electrical connector.
Inspect the exhaust system for leaks and underbody contact.
Lower the vehicle.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.