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.

SYS.OK|MANUAL.DB● LIVE

HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1877 (ENGINE EXHAUST SYSTEM)REPAIR INSTRUCTIONSCATALYTIC CONVERTER REPLACEMENT - LEFT SIDE (LZ4)INSTALLATION PROCEDURE

2003 Chevrolet TrailBlazer 4.2 S, 4WD

Installation Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Installation Procedure

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Catalytic Converter To Intermediate Muffler Nuts

Courtesy of GENERAL MOTORS CORP.

Install the catalytic converter gasket onto the catalytic converter.
Reposition the muffler assembly rearward until the catalytic converter can be installed.
Install the catalytic converter.

CAUTION: Refer to Fastener Caution .

Install the catalytic converter nuts (1) and tighten to 60 N.m (44 lb ft).
Remove the support from the exhaust system.

Fig 2: Left Side Catalytic Converter To Exhaust Manifold Nuts

Courtesy of GENERAL MOTORS CORP.

Lower the vehicle.
Install the left side catalytic converter to exhaust manifold nuts (1) and tighten to 35 N.m (26 lb ft).

Fig 3: Left Side Exhaust Manifold Heat Shield Bolts

Courtesy of GENERAL MOTORS CORP.

Install the exhaust manifold heat shield.
Install the left side exhaust manifold heat shield bolts (1) and tighten to 10 N.m (89 lb in).
Install the HO2S sensor. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready Tools Free Quote Check Quote Shield Pro

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.