Is Your Car Sounding Like a Monster Truck? Here’s How to Check if Your Catalytic Converter Has Been Stolen

Dear Mike,

I recently noticed that my car sounds louder than usual. A friend of mine mentioned that this could be a sign that my catalytic converter has been stolen. I’m not sure what to look for to confirm if this has happened. Can you offer any advice on how to determine if my catalytic converter has been stolen?



Dear Corbin,

First off, I want to assure you that you’re not crazy – that loud sound coming from underneath your car is indeed abnormal. Unfortunately, your friend might be right about the stolen catalytic converter.

In case you didn’t know, a catalytic converter is an important component of your car’s exhaust system that reduces harmful pollutants released into the air. The valuable materials inside, like platinum, make them a hot commodity for thieves. Plus, they’re relatively easy to remove from underneath your car.

So, how can you determine if your catalytic converter has been stolen? There are a few telltale signs:

1. Loud Exhaust Noise: As you’ve mentioned, a stolen catalytic converter will cause your car to suddenly sound like a monster truck. It’s because the exhaust gases are no longer flowing through the converter, which helps to muffle the sound.

2. Dangling Exhaust Pipes: If the thief simply hacks off the converter, the remaining exhaust pipes will no longer be supported. You may notice them hanging lower or tilting to one side.

3. Strange Vibrations: Without the weight of the catalytic converter, your car may feel more bumpy or shaky than usual. This could also be accompanied by a rattling or clunking sound.

If you notice any of these signs, it’s important to take action quickly. Not only will a missing catalytic converter cause your car to fail an emissions test, it’s also illegal to drive without one in most places.

So, what can you do to prevent this from happening in the first place? As you mentioned, some aftermarket kits are available to help deter thieves. These usually involve adding a metal shield or cage around the converter to make it harder to access. But as you noted, these kits aren’t available for all makes and models.

Your best bet is to park in a secure, well-lit area, preferably indoors if you have access to a garage. If that’s not possible, park in a spot where it’s difficult to get underneath your car, like against a curb.

Lastly, if you do become a victim of catalytic converter theft, I recommend contacting your insurance company right away. Depending on your coverage, they may be able to help with the cost of replacement.

Stay safe and happy driving!

Mike Urban,
Founder of Urban Automotive