Top 5 Signs Your Catalytic Converter is Clogged

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The catalytic converter, you can’t have a car without it, but you also don’t want one! Here are the top 5 reasons you may need to replace your catalytic converter over time.

So what are some signs your catalytic converter has gotten clogged? Firstly, your check engine light has likely turned on, however there are other ways to tell, such as exhaust in your cabin, the vehicle not running right, or even that there is a burning smell! If you run into these issues, make sure to get your catalytic converter replaced ASAP.

1. Check Engine Light

Something I have learned over time, is that if your check engine light is on, it is cheaper to just have the problem resolved, even if it is a small problem.

A failed catalytic converter is a common reason why a check engine light may be illuminated! If you have this light come on, its best to have it checked out and fixed as soon as possible.

Thankfully cars have check engine lights to warn us about issues like this, otherwise you could run into a lot bigger issues than a bulb showing up on your car.

2. Exhaust in the cabin

Exhaust is what is making its way through the catalytic converter, and because of that, if it gets clogged, it has no where else to go but out. This results in the exhaust not making its way out the rear of the vehicle, and instead can and will get pushed out into the cabin itself.

This is one of the easiest ways to tell if your catalytic converter is clogged, as there aren’t many reasons as to why exhaust would end up in the cabin of your vehicle.

Not only is this sign not a good thing for your car, but it also is not healthy for you to breathe, and should get fixed right away.

3. Vehicle not starting or running right

A vehicle needs airflow to work, not just intake but also expelling that air! When a catalytic converter is clogged, it is unable to get rid of their that it takes in, causing the vehicle to stall or just not start at all.

Generally speaking though, by the time you are at this point, you likely have had plenty of other signs from this list popping up over time.

4. Burning smell

One of the big things that happens when your catalytic converter gets clogged, is that it also gets hot, like really hot. Because of that, you might begin to smell a burning smell if your catalytic converter gets bad enough.

Yes, it can even catch on fire, so this isn’t something you want to mess around with at all!

This is probably one of the main things that if you smell, stop driving, pull over and get yourself a mechanic ASAP. This will help you from having your vehicle burn to the ground. Because, you know, fire.

5. You have had a recent engine failure

Have you recently had your engine fail, and subsequently replaced? This can actually cause your catalytic converters to fail. Okay, replacing it won’t, but the initial failure of the engine can fail.

Basically what has happened is shrapnel from inside your old engine has made its way into the catalytic converter, messed it up, and caused them to fail. If your car’s engine has had a catastrophic failure, I would highly recommend having your mechanic verify a catalytic converter failure hasn’t happened as well.

Unfortunately due the catalytic converter cost, this may mechanically total a lot of cheaper vehicles out there, so this should really be accounted for ahead of time.

Why does a Catalytic converter get clogged?

There are plenty of reasons a catalytic converter can fail over time! There is of course just standard usage, causing it to wear out. It can also be caused by coolant making its way into the converter, or even oil.

Want to learn more about a catalytic converter? This article might be a great read for you.

Buying a police car can cause a bad catalytic converter

Did you know that police cars sit, but stay running for long periods of time every day of the year? This actually can cause your catalytic converter to fail at an earlier mileage if you buy one from your local police department.

Even though the car may not have a crazy amount of mileage on it, it has been running and using not only the engine but also the catalytic converter over time.

Frequently Asked Questions

Can a car run without a catalytic converter?

Cars can actually run without a catalytic converter no problem, however it may be illegal! These catalytic converters are used to reduce emissions by quite a bit, and the government isn’t too keen on your removing it and causing emissions to come out your tail pipe.

How does a car sound without a catalytic converter?

Catalytic converters play a big part of taking away the sound of your vehicle, so a vehicle is actually much louder without one. That said, this should only be done within your local, state and federal laws, which generally means it will only be used for off-road or track days.

Why is a catalytic converter so expensive?

Catalytic converters have a wide range of minerals and metals inside of them, this high density of expensive metals make construction and the sale of a converter rather high.


Make sure you pay attention to that check engine light and get whatever is the problem fixed! This is even if it is not catalytic converter related. The big issue that a lot of people run into, is leaving their check engine light on due to it being a small issue, and when a big issue happens they have no idea that it has happened.

I hope this article helped you not just learn that, but also learn about all five ways that you can tell if your catalytic converter has gotten clogged!