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6 Best Catalytic Converter Cleaners – (Reviews & Guide 2021)

Years ago, researchers, government agencies, and automakers saw a huge need to stem the massive flow of harmful compounds that automobiles put into the atmosphere as they were driven. Out of that need, catalytic converters became mandatory equipment on cars. For the most part, they were very effective at curtailing the flow of pollutants into the air but it came at a cost. Sometimes catalytic converters would become dirty and severely hurt the performance of your vehicle. When that happens, the best catalytic converter cleaner will help restore your car’s performance to normal.
In this article, we will tell you all about catalytic converter cleaners and how to shop for them. We will even do several catalytic converter cleaner reviews on the best ones available in the marketplace. So the next time your car’s catalytic converter becomes dirty and causes your car to act up, you will know how to deal with it.

Best Catalytic Converter Cleaner Reviews

1. Motorkote MK-10351-06 Catalytic Converter Cleaner

Motorkote MK-10351-06 Catalytic Converter CleanerHere is a very good catalytic cleaner from Motorkote that also has some other nice benefits for your car’s exhaust and fuel system. Once you use it will do such things as lower phosphorus and zinc retention levels at the catalytic converter inlet. It will also lower exhaust pipe emissions too. This makes it a good product to use shortly before getting your vehicle’s emissions tested. In some cases it works so well it may get rid of a P0420 catalytic converter sensor light code.
This product is simple to use. All you do is add 1 whole bottle after filling up your vehicle’s gas tank. It will even clean up your fuel system’s oxygen sensors too. Just one use can save you from having to replace your entire catalytic converter.


  • Reduces phosphorus and zinc retention levels at inlet
  • Lowers exhaust pipe emissions
  • Helps clean up oxygen sensors
  • Protects the catalytic converter from harmful oils
  • Helps eliminate P4032 (catalytic converter) check engine light code
  • Can help avoid replacing catalytic converter


  • Only recommended for use when sensor light is on
  • Only a single-use bottle

2. MotorPower Care Catalytic Converter Cleaner Pass Emissions

MotorPower Care Catalytic Converter Cleaner Pass EmissionsDid your car just barely fail its last emission test? Then MotorPower might have the answer here for you with this catalytic cleaner product. It removes soot and carbon deposits throughout the entire exhaust tract. Often times, this is enough to gain you a few points and help you pass your emissions test.
This product works on all different types of engines including hybrid electric and diesel. It will protect exhaust deposit buildup with regular use and it will help with fuel efficiency too. It’s also easy to use a product that you just add to a full tank of gas (15 gallons per bottle).


  • Removes soot and carbon deposits
  • Gains you a few points on emissions tests
  • Protects against exhaust deposit buildup with regular use
  • Increases fuel efficiency
  • Mix with a full tank of fuel
  • Works in diesel and hybrid engines too


3. CRC 05063 Guaranteed to Pass Emissions Test Formula

CRC 05063 Guaranteed to Pass Emissions Test FormulaHere is a catalytic converter cleaner that guarantees you will pass an emission test after you use it. If you don’t, CRC says they will give you double your money back. That’s some impressive confidence in their product.
It is a catalytic converter cleaner that uses powerful detergent additives to clean out not only your catalytic converter but your entire fuel system. It’s simple to use and with repeated use, both your fuel economy and acceleration rate will improve. In some cases, it can even get rid of a faulty catalytic converter P4032 code.


  • Double your money back emissions test guarantee
  • Powerful detergent additives clean the entire fuel system
  • Simple to use
  • Regular use improves gas mileage and acceleration.
  • Sometimes helps eliminate P4032 (catalytic converter) check engine light code
  • For use with all type of gasoline including ethanol blends


  • Most effective when used more than once
  • Only a single-use bottle

4. Solder-It (CAT-1) Catalytic Converter Cleaner

Solder-It (CAT-1) Catalytic Converter CleanerIf you often get that rotten egg smell from your catalytic converter as you drive along this product can help. This catalytic converter cleaner from Solder-It not only cleans but it deodorizes at the same time. It is a catalytic converter cleaning product that will help clean your entire emission system and may very well help you pass your next emission test too.
This is a simple gas additive product that you will see other benefits from too. Regular use will also improve the performance of your engine’s oxygen sensors and it can help increase the time between engine tune-ups for you. For some, it has helped them pass their emission tests too.


  • Gets rid of rotten egg smell
  • Cleans and deodorizes your emission system
  • Improves oxygen sensor operation
  • In some cases will help you pass an emission control test
  • Extends time between tune-ups
  • Simple to use a gas additive


  • Not proven 100% effective for passing emission control tests
  • Only on occasion will it help eliminate a P4032 (catalytic converter) check engine light code

5. Cataclean 120018CAT Fuel And Exhaust System Cleaner

Cataclean 120018CAT Fuel And Exhaust System CleanerCleaning up your catalytic converter has many benefits for your automobile but this cleaner from Cataclean takes that to a whole new level. It has great benefits for your entire fuel and emission systems. It does this by eliminating harmful carbon buildup throughout these critical vehicle systems.
This generous 3-liter size bottle treats up to 30 gallons of gasoline. Once applied it will even benefit such essential parts of your fuel system as your oxygen sensors, fuel injectors, and your cylinder heads. It is an effective emissions system treatment that will work on all types of gasoline engines.


  • Restores and helps maintain the catalytic converters
  • Reduces excess carbon buildup
  • Benefits oxygen sensors, fuel injectors, and your cylinder heads
  • Treats the entire fuel and emission system
  • Works on all gasoline engines
  • 3-liter bottle treats 30 gallons of gas


  • Does not work on diesel engines
  • Not intended to get rid of catalytic converter check engine codes

6. OXICAT – Oxygen Sensor & Catalytic Converter Cleaner

OXICAT - Oxygen Sensor & Catalytic Converter CleanerHere is a catalytic cleaner that can greatly benefit your car’s catalytic converter and exhaust system with regular use. It’s a gasoline additive that does a nice job of dissolving harmful soot and carbon deposits that can severely hurt your engine’s performance.
This OXICAT catalytic converter cleaner works in gasoline, diesel and hybrid-electric powered vehicles. It does a nice job of cleaning up your oxygen sensors too. For those with who are borderline in passing their emissions tests, it may just put you over the top there too. This German brand exhaust cleaner has been proven to work for many years there.


  • Helps clean up your catalytic converter and oxygen sensors
  • Cleans the entire exhaust system with regular use
  • Dissolves soot and carbon deposits
  • May help you pass your emission test
  • Works in Diesel and Hybrid-electric engines too
  • Proven German Chemistry


  • Only starts working after the car has been driven for a while
  • Needs to be used repeatedly for best results

What Is A Catalytic Converter?

Best Catalytic Converter Cleaners

Many people know that their car has a catalytic converter and it’s an anti-pollution device but many don’t know much more than that about them. We will go over a little bit more detail about what a catalytic converter is.
First of all, a catalytic converter is part of your vehicle’s exhaust system. In almost all cases it is located on your exhaust system somewhere after the engine manifold and before your muffler. As a matter of fact, many people often mistake a catalytic converter for a muffler because they are similar in size and shape.
As the exhaust from your car passes through your catalytic converter a chemical reaction takes place in them. This chemical reaction turns the once harmful and polluting exhaust into more environmentally friendly byproducts. There are three main pollutants that these devices are meant to help eliminate. They are:

  • Carbon monoxide – a byproduct of combustion
  • Hydrocarbons – gasoline that does not completely burn up in the engine
  • Nitrogen oxides – produced from the heat of a car’s engine

A catalytic converter is designed to turn all three of these harmful pollutants into much less harmful byproducts. It does this using adding catalysts into the exhaust that passes through them. These catalysts are platinum and palladium. Both of these elements are placed either in beads in your catalytic converter or coated onto a honeycomb-like structure.
The chemical reaction that takes place in your catalytic converter makes deadly carbon monoxide into harmless carbon dioxide, turns smog-producing hydrocarbons into carbon dioxide and H2O, and converts acid rain causing nitrogen oxides into nitrogen and oxygen.
These have been required pieces of equipment on all new cars manufactured in the United States and other countries since 1975.

Catalytic Converter Cleaner Buying Guide

Catalytic Converter CleanersHere are the main things to consider when buying any type of catalytic converter cleaner:

  1. Compatible engine types

    The very first thing you have to check on any catalytic converter cleaner is if it’s compatible with your engine type. Some cleaners will only work with gas, diesel or hybrid-electric engines while others can be used in all three. It’s important to know this before you make your purchase. This information will clearly be stated on the packaging and the manufacturer’s website.

  2. How it works/What they target

    There are different ways that catalytic converters work and different problems that these catalytic converter cleaning problems address. You want to pick one that most closely relates to the problems you are experiencing with your catalytic converter and emissions system. If you are just looking for a catalytic converter cleaner that will provide general maintenance, then find one that will clean both your fuel and emissions systems.
    Some catalytic converter cleaners are aimed at doing such things as getting rid of the rotten egg smell. Others claim they can help you pass an emission test or will do such things as improve your acceleration. There are even those catalytic cleaner formulas that claim they may help eliminate a P4032 (catalytic converter) check engine light code.
    So make sure you know what you are buying a catalytic converter cleaner to help you with in your car.

  3. Does it offer protection after use?

    Some catalytic converter cleaners offer protection for your car for extended periods of time after they have been added. Others are single-use products that do their cleaning job and then do not work again until more of the product is added.
    The ones that offer catalytic converter and exhaust protection for a longer period are nice to use. They do such things as help keep soot and carbon from building up inside your car’s exhaust. Many offer protection against oil and other undesirable chemical buildups in your exhaust system too.

  4. What other fuel and exhaust system parts does it clean?

    Many people who use catalytic converter cleaners choose brands that will not only clean the catalytic converter but that will also clean other parts of their car’s fuel and emission systems. So be aware of the catalytic converter cleaner you choose can also clean such fuel and exhaust system parts as your cars:

    • Oxygen sensors
    • Fuel injectors
    • Cylinder heads
    • Other areas of your exhaust system

    This added cleaning will help your car’s performance and help extend its fuel mileage.

  5. Size/Mixture

    A Catalytic converter cleaner can come in different shapes and sizes. Most of them come in single-use applications but there are exceptions to this too. Some come in larger containers that are good for multiple numbers of treatments. These are preferred for those types of catalytic converter cleaners that work best when used regularly.

  6. Can it help you pass emissions tests?

    Many people like to add a catalytic converter treatment right before they get an emissions test. They feel it may give them a better chance of passing this test. But you better make sure you read the recommendations on the packaging before you purchase your catalytic converter cleaner to make sure it can help with this. Most types of catalytic converter cleaners that will help you pass an emissions test will clearly state that on the packaging.

  7. Does it help eliminate a P4032 (catalytic converter) check engine light code?

    One common problem that people rely on catalytic converter cleaners to help with is a P4032 (catalytic converter) check engine light code. You must realize there is never a guarantee that any catalytic converter cleaning product will fix this check engine light code. The ones that say they can do this will give you the best chance at turning your check engine light off after you use them.

  8. Guarantee

    Some manufacturers have much confidence in their catalytic converter cleaning products. So much so, that they will even guarantee them. We have already seen one example of a company in our reviews that offers a double money-back guarantee if you use their catalytic cleaner and you do not pass an emissions test. It’s good to be aware of what cleaners come with such a performance guarantee before you buy them.

What Causes Catalytic Converter Problems?

Your car’s fuel and emissions system are much more complex systems than you would probably imagine. What makes them complicated is the fact that so many parts in these two systems must mesh together just right to keep your fuel and exhaust systems performing at an optimal level. There are, however, certain things that often keep that from happening in your vehicle. One of those is the buildup of carbon, soot and other undesirables in your catalytic converter. Some of the main auto problems that cause soot and carbon to build up in your catalytic converter are worn piston rings, improper valve seals, bad gaskets and spark plugs that misfire.

How Catalytic Converter Cleaners Work?

It was just mentioned that soot and carbon from poor working engine components tend to find their way into your car’s catalytic converter. When this happens they start to coat the beads or honeycomb-shaped parts that contain the catalyst in them. Once this happens it makes it difficult for the catalysts to do their job and convert harmful exhaust in harmless byproducts. When you add catalytic converter into your fuel system it will eventually end up in your catalytic converter and start to remove the soot and carbon buildup. This allows the catalysts in the catalytic converter to once again do their jobs.

Is Catalytic Converter Cleaner Safe to Use?

Catalytic converter cleaners contain no chemicals in them that are corrosive to engine parts. That means that they will not harm your catalytic converter or any other engine parts as long as you follow the directions on the packaging. They are considered a very safe product if used as instructed.

How Often To Use Catalytic Converter Cleaner

This varies a little bit depending on the product. But make no mistake about it; catalytic converter cleaners are most effective when used regularly. Some cleaner manufacturers say that you should add them every 3,000 miles but that might be a little too often. As a general rule, you can probably find a spot that works well for you between 5,000 to 10,000 miles. You can adjust this up and down depending on how your engine and your catalytic converter are performing.

Benefits of Using Catalytic Converter Cleaner

There are many good reasons to use a catalytic converter cleaner regularly. Here are some of the main benefits you get from having soot and carbon-free catalytic converter.

  • Smoother acceleration
  • Better engine performance
  • Increased fuel efficiency
  • Gets rid of rotten egg smell
  • Cleans and deodorizes your emission system
  • Improves oxygen sensor operation
  • In some cases will help you pass an emission control test
  • Extends time between tune-ups

How to Clean Catalytic Converters

Catalytic converter cleaners are very simple to use. They are a gasoline additive in a large majority of the cases. You simply fill up your car’s gas tank and add the proper ratio of cleaner to the amount of gas that your tank holds. The catalytic converter cleaning products work as you drive so there is nothing special you have to do once you add them.

Catalytic Cleaner FAQ’s

Here are some of the most common questions we receive about catalytic converter cleaners.

  • Question: Should I add catalytic converter cleaner regularly or only when I start noticing performance problems and that rotten egg smell associated with catalytic converter problems?
    Answer: Without a doubt, regular treatment of your car’s fuel and emission system with catalytic converter cleaner is the best way to go here. Often when you start experiencing catalytic converter problem symptoms it may be too late to reverse the damage. On the other hand, if you treat your catalytic converter regularly you may never experience problems with it at all.
  • Question: What causes the sulfur smell or what some people refer to as a ‘rotten egg’ smell from my catalytic converter? Can a catalytic converter cleaner help with this?
    Answer: Your catalytic converter is designed to change harmful hydrogen sulfide into sulfur dioxide. Most of the hydrogen sulfide gets into your catalytic converter because fuel is not always being burned off properly in your engine. When you detect sulfur or ‘rotten egg’ smells at times it means your catalytic converter is no longer performing this chemical change properly. In some instances, a catalytic converter cleaner can help clear up this problem but not always.
  • Question: What are some of the signs that indicate that your catalytic converter is not working properly even after you use catalytic converter cleaner?
    Answer: There are some warning signs that your car will give you to indicate you may be having catalytic converter problems. They include:
    Reduced engine performance and poor acceleration
    Smelling sulfur or ‘rotten eggs’ regularly
    A rattling noise coming from your exhaust system
    Check engine light with P4032 code
    Failing an emissions test
  • Question: What is the most important consideration when adding a catalytic converter cleaner to your car?
    Answer: Without a doubt, it’s reading the instructions on the specific catalytic converter cleaner that you purchase. That will tell if it’s compatible with your type of engine and exactly how best to add it into your fuel system. Failure to do this can lead to some huge problems.

When you’re done, read our oil additives buying guide, engine degreaser reviews and best fuel injector cleaners round-up.

Wrapping Up

We don’t see any reason why you shouldn’t periodically add a dose of the catalytic converter to your car’s fuel every so often. There is a good chance it will improve your vehicle’s performance and help it exhaust its emissions properly. There is also almost zero chance that they will have any negative impact on your vehicle. As a matter of fact, the best catalytic converter cleaner products have been shown to reduce exhaust system buildup and improve a car’s performance.
Our catalytic converter cleaner buying guide can be used as a good guideline of what to look for when you want to purchase a catalytic converter cleaner. You can also never go wrong by purchasing any of the cleaning products that we did catalytic converter cleaner reviews on. So be proactive when it comes to taking care of your fuel and exhaust systems and periodically add some catalytic converter cleaner to your vehicle.