Can You Punch Out a Catalytic Converter?

by Michael Davidson
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The breakage. image by FAFANJA from

The catalytic converter is an anti-emission device in an automobile exhaust system that is designed to burn off harmful chemicals before they can be released into the environment. If a converter starts to break up internally, the fragments can block the exhaust from passing through and the car can start running roughly. Punching out the converter is a temporary fix for this problem that can help you get the car to a mechanic for a proper repair.


"Punching out" the converter is the process of adding holes into the converter casing in order to allow additional airflow through the converter, which bypasses any blockages in the device. The procedure is effective for restoring the engine performance that is lost by a clogged converter, but it is illegal in most states to keep the converter in that condition since the exhaust system is no longer properly burning off emissions.


You can punch out a converter in several ways. You can just crawl under the car with a hammer and a sharp chisel and create holes in the converter by hammering the chisel into it. A more precise procedure is removing the converter first by either unclamping it from the exhaust system or by sawing it off if it is welded on. There is a pipe that runs out of the device on both sides that can be easily cut through. Once the converter is removed, it is easier to hold it in place while you chisel holes into it and then it can be reattached.


Punching out a catalytic converter is illegal in most states because of the emissions released by the car once the catalytic converter is no longer functioning; check the laws of your state before attempting it. Punching out the converter can be necessary if your car is not starting or running properly because of a severe blockage, and this procedure will make it easier for you to get the car safely to a mechanic without the car stalling. If a mechanic sees the converter is missing or not working properly, he is required to replace it if licensed in a state that requires a working converter.

Valuable Metals

Catalytic converters contain valuable metals such as platinum, rhodium and palladium. If you are scrapping your car outright, you can punch out the converter to break up and extract the metals then sell them to metal recycling centers.

Converter Theft

The use of platinum and other metals inside of catalytic converters has resulted in a rise of converter theft; thieves punch out the converters and steal the metals out of them, leaving the owner with a missing or damaged converter that he is legally required to repair. Because a converter replacement can cost hundreds of dollars, law enforcement agencies have tried to crack down on this type of crime.

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