How to Replace an Exhaust Catalytic Converter

The catalytic converter happens to be one of the most expensive parts of a car to fix, which leads many people to try to repair it at home. You have to know your way around cars and exhaust systems, or you're honestly better off taking it to a mechanic. If you're comfortable working on it yourself, there are a few things you should keep in mind.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Ramps
• O2 wrench
• New catalytic converter

1. Lift your car. Unfortunately, the catalytic converter sits about midway down the length of your car, so lifting one end or the other will not do. Ramps are your best bet to get you within reach of the parts when working from home. Luckily, this is usually the hardest part of this repair.

2. Be patient with the bolts, as they are often hard to remove due to size and awkward placement. You may have to drill or saw bolts to remove them. With this in mind, you should pick up new bolts, nuts and seals for your replacement project.

3. Buy a catalytic converter specific to your car to avoid extra work. A generic part must be welded into the car, while a vehicle-specific model comes pre-welded to the proper pipes for easy bolt-on installation.

4. Remove the 02 sensor (with an O2 wrench) before unbolting the catalytic converter. Then, you should remove the pipe connecting the sensor to the converter. Depending on your exhaust system, you may have to remove more pipes before you unbolt the converter from the muffler.

5. Replace the old catalytic converter with a new one. This should be the easy part, as you simply bolt the new part in place.

6. Reattach the exhaust pipes and 02 sensor, and the basic job is done. Make sure you replace any cracked or rusty pipes while you have the exhaust system apart.

Tips & Warnings

• Catalytic converters often fall under a separate emissions warranty that lasts at least 7 years and 160,000 miles. Even if your car is out of its regular warranty, but it is a newer model, ask your dealer to replace the part for you free of charge.
• Rent the O2 wrench or socket if you do not own one. Most auto parts stores carry this tool for rentals.
• In many states, older (vintage) cars do not need a catalytic converter, so you can gut it or remove it completely. No damage will result from running a car without a converter.
• Due to emissions standards, it is illegal to buy or install used converters.