Gutting a Catalytic Converter

catalytic converters
  • 10-20 hours
  • Advanced
  • 0-700
What You'll Need
Pneumatic lift or high-frame jacks
Acetylene welding torch
Arc welder with steel wire
Air compressor
Powered grinding wheel
Protective welding face mask
Fireproof gloves
Steel putty knife
Ball peen hammer
Broad-nose pliers
Cold-weld epoxy

As your catalytic converter gets older, it may become clogged, reducing your vehicle's fuel efficiency and making it run rougher. Luckily, you can check up on your automobile's catalytic converter to see if any work needs to be done.

Uncouple the catalytic converter from the muffler of your car. If the car's engine immediately sounds smoother and less rattly, your catalytic converter is plugged. If you need to gut the catalytic converter on your vehicle, follow this process to do so without having to remove it.

Step 1 — Raise Your Vehicle off the Ground

Put your vehicle up on a pneumatic lift or a set of high-frame jacks with blocks to do repairs to the catalytic converter while it stays on the vehicle.

Step 2 — Find the Converter

On most vehicles, the catalytic converter is placed in front of the muffler, toward the engine block.

Step 3 — Make Specific Cuts in the Converter Base to Create A Flap

Use the wheel grinder or the acetylene torch to make three cuts at right angles in the base of the converter. Do not cut out a complete square hole, or you will need to replace the converter immediately. Allow the catalytic converter to cool back to air temperature. Use the crowbar to bend down the flap you have cut.

Step 4 — Break Apart the Ceramic Lining of the Converter

Use the hammer and chisel to chip away the lining of the catalytic converter. It is in the form of a honeycomb, and you can break it up easily with small, well-placed taps of the hammer. Ensure you have removed all the ceramic pieces from inside the converter.

Step 5 — Close the Flap

With the broad nose pliers, bend the flap you cut back up into place, to close the bottom of the converter as tightly as possible.

Step 6 — Weld the Flap Shut

Put on the welding mask and gloves, and then weld the flap shut with steel strips melted to fit with the welding torch. Use the medium to medium-high setting of the welder to effectively melt the steel wire. Use a steel putty knife to smooth the welded metal while it is hot.

Step 7 — Check for Leakage

When you start the engine of your vehicle, extra-loud echoing noise, rattles, or a hissing sound will tell you there are still air leaks in the catalytic converter. Fix the leaks with cold-weld epoxy used to seal perforations in automotive exhaust systems.

Step 8 — Other Options

You can also clear the catalytic converter after removing it from your vehicle. With the engine off, remove the rear exhaust clamp and the exhaust pipe. Detach the converter from the exhaust pipe in front of the muffler. Shake the converter gently; if it rattles, heat has caused the ceramic inner lining to disintegrate. If you hear no noise, the converter is clogged with unburned fuel. Either way, it needs to be replaced as soon as possible.