A bad catalytic converter isn't something to ignore as it may cause your ride to run rough and have poor mileage. But having a qualified mechanic replace this component can be very expensive, so if you have a bit of automotive mechanical and basic D-I-Y tools, you'd better do the replacement by yourself. Here's a step-by-step guide on how to remove a bad cat con and install a new one:
What you'll need:
- Replacement catalytic converter and gaskets
- Jack stands
- Car jacks
- Wooden blocks
- Penetrating oil/Lubricant
- Socket wrench
- Breaker bar
Step 1: Raise the car. Make sure that your ride is parked on a flat ground, the emergency brake is locked, and the exhaust has cooled down before raising the car. If you don't have a lift, you can either raise the vehicle and jack up all four wheels or just raise the rear end up to a height that can accommodate you underneath, jack it up, and chock the wheels that still touch the ground. Be sure that all the jack stands are securely placed under the vehicle's heavy frame spots.
Step 2: Find your way under the car and assess the exhaust system's condition. Lie on your back, go under the vehicle, and assess the condition of the cat con and the entire exhaust system as well to find out if there are other parts that need replacement.
Step 3: Test-fit the catalytic converter and all the needed parts and hardware. Before installation, you can visually test-fit the cat con to see if it's an accurate replacement for your stock.
Step 4: Remove the O2 sensor and spray penetrating oil to connecting bolts. With a socket wrench, remove the oxygen sensor from the cat con and set it aside. Determine where the cat con connects to the exhaust and spray penetrating oil on the bolts that secure it in place. With the socket wrench or breaker bar, loosen these bolts.
Step 5: Remove all the bolts that hold the cat con in place. Start with the bolts at the rear and work your way to the front. If your exhaust system comes with a heat shield, you have to take it off also.
Step 6: Remove the old catalytic converter. Once the bolts have been removed, it should be easy for you to take the cat con down. If it's stuck, break it free using a hammer; just be careful enough not to hit its neighboring components.
Step 7: Replace the gaskets and install the new cat con. Make sure that the new gaskets are in their proper positions before fitting the replacement cat con.
Step 8: Reinstall the bolts holding the catalytic converter in place. To correctly align the bolts, it's wise to finger-tighten the nuts on the bolts first before tightening them all down. You may need someone to hold the cat con while you're working with the bolts.
Step 9: Put the oxygen sensor and heat shield back in place. It's also the right time to check your O2 sensor wiring for nicks and other forms of damage.
Step 10: Re-check for loose bolts and any gap between two adjacent parts. This is to make sure that there will be no leaks or gaps in the bolted connections or in your O2 sensor.
Step 11: Carefully remove the vehicle from jack stands and start it. Listen to how the engine runs and peek under your vehicle to see if there are exhaust leaks. If there's none, then your car is now ready to drive.