Keep your catalytic converter from being stolen

A combination of behaviors and devices can reduce the odds of your "cat" getting ripped off.

Thieves are stealing catalytic converters from cars at alarming rates to cash in on the precious metals inside them. Average replacement cost "is getting near a thousand dollars as the cost of the converters just keeps going up," says Don Johnson, proprietor of Johnny Franklin's Mufflers in San Rafael, California. "On the higher end it can be $3,000," he says, especially for a truck or large SUV that may have dual exhausts and much larger catalytic converters.  

Cats contain a small but expensive amount of precious plating metals that include platinum, palladium and extremely costly rhodium which are the catalysts for a chemical reaction that reduces toxicity in exhaust. A New York Times report in February estimated the overall auto, parts and repair industries will spend $40 billion on precious metals to make cats this year.  As long as the prices for the precious metals remain sky high, catalytic converters may remain an attractive target for thieves who sell them into an illicit metal recovery or "washing" market.  

Here's what you can do to protect the "cat" in your car. 

  • Have a catalytic converter guard installed. These range from nice bolt-on premade metal guard plates to crude DIY (but cheap) rods of rebar welded around your cat to make it harder to get it out. There are some downsides, including cost and potential complications when you need to get your car smog checked or have its exhaust system repaired. But those are fairly small annoyances compared to the cost and hassle of replacing a stolen cat.
  • Park in a place that makes it hard to get under the car. Even blocking a couple of sides may convince a thief to move on to the next car.
Catalytic converter assembly

A typical dual cat assembly.

Walker Exhaust
  • Be particularly careful where you park a truck or SUV as they have higher ground clearance that almost beckons a thief to slide under them. Those kinds of vehicles also tend to more and more expensive cats than a smaller vehicle, further increasing the attraction to thieves.
  • Park where traffic, pedestrians, or police are more likely to pass by. I would also say park in a well-lighted place, but judging by some cat theft videos it seems to make little difference and almost serves as a convenient work light for thieves.  
  • Have a muffler shop inscribe all or part of your car's VIN on your catalytic converter. It won't stop theft but it can help police connect the dots if they catch a thief with stolen ones.
  • Buy a daily driver made before the mid-1970s like my 1967 Mercury Cougar. No cats, no smog tests!
Catalytic converter security plate

A cottage industry has sprung up around security shields that can be bolted to the underside of your car with tamper resistant screws to block thieves from quickly cutting out your catalytic converter.


By the way, don't follow any loopy advice to remove your cats. They do an important job of "cooking off" and converting most of the nastiest engine emissions into something much less toxic and, will confuse your car's engine control unit if missing and render your car unregisterable in smog test states. Things like catalytic converter bypass or "test" pipes are not a legal way to circumvent emissions equipment requirements on any car that will be operated on public roads.