8 Best Catalytic Converter Cleaners (for Clogged Cats)

Note: This post may contain affiliate links. This means we may earn a small commission for qualifying purchases at no cost to you.

Catalytic converters (not “Cadillac converters” as some may say) reduce engine exhaust toxicity, but over time can get dirty or damaged. While replacement is needed for failed converters, cleaners can often restore dirty ones to proper function.

But with so many options, how can you know which catalytic converter cleaners actually work? I’ve tried many catalytic converter cleaners over the years and here are the only ones I can recommend.

clean exhaust system

See Also: How to Clean a Catalytic Converter (2 Methods)

Top 8 Catalytic Converter Cleaners

If you ever notice your fuel economy decrease noticeably or a rotten egg smell is coming from your engine, then you need to clean the catalytic converter right away. There are many reputable catalytic converter cleaners available on the market. Below are the top 10 cleaners that are most often recommended.

See Also: 5 Best Throttle Body Cleaners

#1 – Cataclean Engine and Catalytic Converter Cleaner

The 16 oz. bottle of Cataclean is one of the best products you can use to clean your catalytic converter and oxygen sensors. Although it is not cheap, the cleaner has a good reputation of clearing various catalytic converter codes from your ECU and is easy to use.

If you need to take an emissions test and you need to quickly clean your catalytic converter and fuel system, this is probably your best bet.

See Also: Tips to Pass a State Emissions Test

#2 – CRC “Guaranteed to Pass” Emissions System Formula

best cat cleanerThe CRC “Guaranteed to Pass” formula actually offers a double money-back guarantee so the company stands behind their product. This solution will remove carbon from your engine, catalytic converter, and fuel injectors.

It’s been used many times to successfully treat a P0420 fault code. Good to use to increase your chances of passing an upcoming smog test. Recommended to use every 3,000 miles.

#3 – Solder-It CAT-1

catalytic cleaner reviewsIn addition to being a cleaner, Solder-It is designed to remove the nasty rotten egg smell from toxic gasses because of its deodorizing properties.

For best results, add it to your gas tank when you have about a quarter of a tank full and drive for about 50 miles before refilling. This stuff is best for removing the rotten egg odor but also cleans your cat converter.

#4 – Oxicat Oxygen Sensor and Catalytic Converter Cleaner

clean catalytic converterMade in Germany, Oxicat is designed to clean the entire exhaust system by removing carbon deposits and soot throughout. When used properly (follow the directions!), it does a great job of cleaning, restoring performance, and even clearing out check engine codes such as “catalyst system efficiency below threshold”

As with any other cleaner, it needs the catalytic converter to sustain working temperature while driving so if you cat is damaged or cracked, a cleaner won’t help you.

Read Also: Is Driving Without a Catalytic Converter Legal?

#5 – Hi-Gear HG3270s

emissions pass cleanerUse Hi-Gear to clean your catalytic converter, exhaust system, fuel system, valves, and pistons. You will likely notice better fuel economy and engine performance after using.

If you’re in danger of failing your emissions test, it’s worth trying and many users have reported it being able to clear out their emissions related trouble code without having to spend hundreds on a new parts.

#6 – Sledgehammer Run-Rite Kit

fuel system cleaner kitThe Sledgehammer Run-Rite kit includes both a bottle of Fuel System Ultra Cleaner and the Rapid Induction Deposit (RID) cleaner to work together in cleaning your fuel and exhaust systems.

This is formulated to get rid of soot and carbon which may exist in the fuel system, particularly the catalytic converter. Since you need to add the contents of RID directly into a vacuum line to release into the intake, it’s not recommended for beginners.

#7 – Sea Foam Motor Treatment

Seafoam engine cleaner reviewWhile the popular Sea Foam treatment won’t clean your catalytic converter, it treats the problems prior to that which cause the converter to get clogged up in the first place.

Many individuals have actually had fault codes related to the catalytic converter go away after using. At the very least, you’ll give your fuel injectors and combustion chamber a good cleaning.

Also Recommended:  Best Fuel Injector Cleaners

#8 – Lucas Fuel Treatment

Lucas fuel treatmentLike Sea Foam, Lucas Fuel Treatment treats the problems of a dirty fuel system which is often responsible for a dirty catalytic converter. By treating those problems, the engine will run cleaner and allow the converter to burn itself clean.

More than one treatment will be necessary but you’ll be treating the root of the issue so it doesn’t occur again.

Mark Stevens


  1. I have a 2004 Nissan altima sl 2.5. I’m not sure what part of the catalytic converter l need to replace? The manifold or the catalytic converter that’s attached to the exhaust system. Can you tell me what part l need to replace. I know it’s the Cat due to it falls under 4 of the 6 symptoms described.

    1. I’m not sure where the catalytic converter sits on that vehicle. I’d look at a diagram from the manufacturer if you can. Check to see if Nissan’s site has such a diagram with the different parts of the exhaust and their respective part numbers.

  2. I have 2011 Chevy equinox that I put in a can of sea foam due to hearing a rattling noise but it did not clear it but made it louder can I put in a catalytic cleaner in on top of the sea foam. It’s not showing codes but when I start the engine it’s very loud.

    1. Sure you could swap the catalytic converter, but I’m not sure it would fix the issue. You may want to see if the owner’s manual calls for a valve adjustment in that car. Before you do that, try to figure out if the noise is coming from the top end or the bottom end of the engine.

  3. 1993 jeep GC with 6 cyc. Won’t pass california smog due to high HC at idle. 36 pts above the limit. It does pass high speed HC limits no problem. Has new ignition parts and ran SeaFoam through it via the throttle body. Has 200k miles but runs good. Could it be a bad or dirty Cat? It is the original unit. Do you think using this cleaner will be worth it? How do you tell if it is working? Measure the input and output temp.?

    1. I don’t know, I don’t live in California so I have never dealt with their smog test. Have you tried cleaning the throttle body, MAF if it has one, and IAC valve? If it otherwise passes smog, my thoughts are that some of the idle control components may be dirty.

  4. I have a friend that told me he took the cat off his Honda civic and washed it with dish soap and boil.
    Pass the California emissions test.

  5. For my 2007 mazda 3, Can I soak my catalytic converter in a warm water with sea foam auto soap(used for car washing, not the Spray can sea foam) to clean the catalytic converter? Emissions code: PO421

  6. Hi!
    Could I add Seafoam kind plus another actual catalytic converter cleaner to my fuel tank? Or would that be too much going on?

    1. I don’t advise mixing chemicals unless the label specifically says to do so, to avoid the risk of dangerous reactions.

  7. Have a 1999 Jeep Grand Cherokee gets very bad gas mileage but runs good and still has power could cat cleaner improve the gas mileage

    1. Not advisable. There is a ratio of gas vs cleaner for the amount of gas in your tank.
      Should wait until you’re down to 1/4 tank or approximately 4 gallons of gas in your tank.
      Most caty cleaners say to pour into tank containing 1/4 tank of gas, then drive approximately 15 miles & then completely fill your tank with gas. Nothing else should be added in that tank of gas.
      Just read the labels on product’s container for exact directions for the caty cleaner you choose to use as it may vary from one brand or product to another.

  8. I have a Ford Focus, that failed it emissions test this year, the mechanic said to try some cataclean through the engine to resolve it. It was less than £20 and a one week later the car passed the test no problem at all.

  9. We have a repair shop and our customers always ask us about catalyst cleaners. So far the best working cleaner is called Motorpower Care catalytic converter cleaner, we noticed it’s new in market but we are expecting it to be popular in short time for its effectiveness.

Leave a Reply

Your email address will not be published. Required fields are marked *