5 Best Catalytic Converter Cleaners – Reviews and Buying Guide

Best Catalytic Converter Cleaner

A catalytic converter cleaner gets used in removing the carbon buildup that reduces the efficiency of a car's catalytic converter.

Catalytic converters cut down the amount of pollution that's produced by a car's internal combustion engine. They're a kind of filter that use chemical reactions to turn harmful emissions like carbon monoxide, nitrogen oxides, and hydrocarbons into less harmful gases.

Over time though, a catalytic converter gets clogged with carbon buildup, resulting in a less efficient filtering of your car's exhaust gases. This, in turn, will result in your receiving a “Service Engine” light from your car.

Cleaning your car's catalytic converter is a simple process using a catalytic converter cleaner and this review shows you exactly how to do that, plus it includes a list of the best catalytic converter cleaner offers in the market.

You can also read other product reviews such as engine degreaser, fuel injector cleaner, carb cleaner.

5 Best Catalytic Converter Cleaners - Reviews

Editor's Rating: 4.2 out of 5 stars (4.2 / 5)

Mr. Gasket Cataclean Catalytic Converter Cleaner

Mr. Gasket's Cataclean cleaner is very popular for the simple reason that it works very well. It's one of the best rated catalytic converter cleaners you'll find and it's based on a patented formula for fuel and exhaust system cleaning, with proven results to go with it.

It will restore your vehicle's catalytic converter, the oxygen sensors, cylinder heads, and injectors. Cataclean's patented formula breaks away carbon deposits along its path, reducing their buildup and cutting down your car's emission levels by up to 50%.

This package includes a 16-oz, easy-to-use bottle with the cleaner, and you can also get a 2-pack for some savings, and even a 6-pack for even more savings.

Usage is simple. Just open the bottle and empty it into your car's partly filled tank and that's it. Repeat in a few months to keep your car well maintained. It's the best catalytic converter cleaner for gas and diesel engines alike.

Cataclean is legal in all US 50 states. It complies with federal low sulfur content regulations, as well as the Volatile Organic Compound (VOC) regulations.


  • Reduces your car's emissions up to 50%
  • Works safely with gasoline, diesel, e.t.c
  • Improves overall vehicle performance
  • Legal in all 50 states


  • It's relatively costly
  • It's not for use in 2-stroke engines

Editor's Rating: 4.2 out of 5 stars (4.2 / 5)

CRC 05063 Guaranteed To Pass Emissions Test Catalytic Converter Cleaner

CRC boasts that you'll pass your emissions test with this cleaner or they'll give you double your money back. Now that's a bold statement, especially coming from a reputable company like CRC.

It comes in a 12-oz plastic bottle and CRC recommends it for treating at most, 16 gallons of gasoline. This formula has the most concentrations of its cleaning agents, making it a very powerful solution that gets fast results.

CRC recommends that you use it every 3,000 miles to keep your vehicle's fuel economy and emission levels healthy. It will work with all kinds of ethanol and gasoline blended fuels.

The price is good and quite affordable when compared to the Cataclean from Mr. Gasket. You can also opt for its 12-pack version, which comes with both lots of savings and 12 pieces of the Guaranteed to Pass Emissions Test or Double your Money Back cards.

It's oxygen sensor safe but on the flip side, it only works on gas engines and CRC makes no mention of its adherence to regulations like the VOC.


  • Guaranteed to help you pass your emissions test
  • Includes powerful detergent additives that act fast
  • Works with all kinds of ethanol and gasoline blended fuels
  • Quickly restores your car's fuel system to like-new


  • Only for gasoline engines

Editor's Rating: 4.3 out of 5 stars (4.3 / 5)

Hi-Gear HG3270e Catalytic Converter Cleaner

Hi-Gear goes straight to the point with its offer here: a good catalytic converter cleaner, at a good price. No fancy stuff, no bells, and no whistles. It comes in a metal can and includes an all-metal cap.

It removes the carbon deposits in your exhaust system and frees it from that rotten egg smell. It also cleans other parts of the system, including the cylinder head, injectors, and the entire exhaust passage, therefore, restoring lost horsepower and increases fuel efficiency.

This Hi-Gear catalytic converter cleaner got formulated just for gas engines, making it of no use for diesel engines. Still, it will work with all blends of gasoline and ethanol fuels.

Unlike most other cleaners in this review, this Hi-Gear offer comes in a metallic can, which is not bad, but it only comes in single cans, with no offer for 6- or 12-pack volume discounts.


  • Quickly removes carbon deposits in the fuel system
  • Cleans out your system and improves horsepower
  • Also cleans the injectors, valves, and pistons
  • Eliminates and prevents rotten egg smell
  • Offered at a low and attractive price


  • There are no volume buying offers
  • Works only with ethanol/ gasoline engines

Editor's Rating: 4.2 out of 5 stars (4.2 / 5)

Solder-It CAT-1 Catalytic Converter Cleaner

Solder-It's CAT-1 catalytic converter cleaner is an effective but slightly expensive solution to clean your car's fuel and exhaust system and to switch off the service engine light.

It's designed exclusively for gas engines and will clean all types of catalytic converters, including the monolithic and the pelleted types. It's also safe for use with the oxygen sensor and helps to clean it as well.

As a deodorizer, Solder-It guarantees that it will remove all traces of “rotten egg” smell from your vehicle's exhaust. Like the other cleaners on this list, it's dangerous for humans though, so handle with care.

Solder-It states that “it may” help in passing the emissions control test. This is a rather weak statement when you consider that there are cheaper cleaners who guarantee to help you pass the test or you get your money doubled back.


  • Cleans your fuel system
  • Also helps to clean oxygen sensor
  • Gets rid of rotten egg smell
  • Works on monolithic and pelleted converters


  • The price is a little high

Editor's Rating: 4.5 out of 5 stars (4.5 / 5)

Autoprofi Oxicat Oxygen Sensor & Catalytic Converter Cleaner

Oxicat stands for oxygen-sensor and catalytic converter cleaner. It's made in Germany, under the Pro-Tec and Autoprofi brands, with both promising a high quality and reliable cleanse.

This catalytic converter cleaner fluid gets developed as a high-performance cleaner that can effectively remove carbon deposits, soot, and all kinds of dirt from your vehicle's fuel and exhaust systems.

Additionally, Oxicat promises to keep your vehicle in top form with regular use. Regular use here translates to 3-5 uses per year. Oxicat aims to cut down a vehicle's emission levels after the tight regulations of the European Union.

This cleaner is safe for use in all kinds of fuel, including gasoline, diesel, and different hybrid vehicles and fuel mixes. It's certified by the German TUV quality and certification agency.


  • Gets rid of all deposits
  • Restores engine performance
  • Protects the system against heavy dirt
  • High-quality and reliable German technology


  • The price is on the high side
  • Its contents are about half the volume of other cleaners

How Catalytic Converter Cleaners Work

How Catalytic Converter Cleaners Work

A catalytic converter cleaner works with chemical reactions to remove the dirt in a catalytic converter and in other parts of a car system. This includes the cylinders, fuel injectors, and other parts of the exhaust system.

Catalytic converter cleaners are solvents, which have been proven to cleanse a car system without having negative effects like causing any damage to any part.

A solvent is any substance that dissolves another substance and in our case here, the solvent breaks down carbon deposits it mixes with along its path through a car's combustion and exhaust system.

These carbon deposits form as a result of improperly mixed gasoline and air mixtures, with more gas than necessary,  which produces lots of unburnt hydrocarbons that like sticking somewhere.

As these hydrocarbons stick on the cylinder sides and exhaust system, including the catalytic converter, they cut down the engine's efficiency by increasing friction in the cylinders, reducing exhaust port diameters, and reducing the amount of the catalytic converter's catalyst surface area.

By simply coming in contact with these hydrocarbon particles, the cleaner breaks down their molecular structure, making it easier for them to get transported out of the exhaust system, and to improve the car's overall performance.

Benefits of Using Catalytic Converter Cleaner Additives

There are obviously, many benefits you can gain from using catalytic converter cleaners, else, they wouldn't be so popular. You should take note though, that no cleaning additive can restore an already failed catalytic converter.

There are four main benefits of these cleaners though, and they're as follows:

#1. Improves Engine Performance

This is one major benefit of using a catalytic converter cleaner. Improperly combusted hydrocarbon particles tend to stick to some engines parts and disrupt their proper functioning, thereby reducing the car's efficiency.

A catalytic converter helps to clean the fuel injection system, which produces more power with less fuel as a result. It also helps to clean the cylinders and cut down on friction, improving overall power as a result.

Any object in the pathway of exhaust gases reduces the engine's performance. As the cleaner cleans out carbon deposits in the converter, therefore, there is less blockage and a corresponding improvement in the engine's performance.

#2. Lowers Emission Levels

A French scientist invented the catalytic converter in the early 20th century to cut down on the level of harmful gases produced by the car's engine. These gases are harmful to the environment and to humans as well.

Reducing the emission level from cars has always been a subject of ongoing debate, with early converters only turning hydrocarbons and Carbon Monoxide into the less harmful Carbon Dioxide. Newer cars since the 1980s additionally include a third converter to convert Nitrogen oxides.

Using a catalytic converter cleaner helps to cut the emission levels of your vehicle to acceptable levels, enabling you to pass the test and additionally be nice to the environment.

#3. Saves You Money

Having a clean engine and exhaust system saves you money in two ways. The first way is that you don't have to spend plenty of money to change your vehicle's catalytic converter because you can clean it very easily.

The second way it saves you money is in lower maintenance and fuel costs. This comes as a result of the car engine's improved efficiency, producing more power with less fuel.

#4. Gets Rid of that Rotten Egg Smell

Any vehicle that's been running rich for a while will develop a rotten egg smell coming from its exhaust pipe, once carbon deposits have caused enough damage in the converter.

When a cleaner works on your car's combustion and exhaust system, the smell also disappears.

Catalytic Converter Cleaner Buying Guide

Catalytic Converter Cleaner Buying Guide

There isn't much to consider when deciding on a cleaner for your car's catalytic converter. This is mainly because of how simple the job is and how similar the cleaning mechanism of all the cleaners are.

Still, there are a few things to check before making your final decision. These factors are as follows:

#1. Compatibility

While many auto catalytic converter cleaners will be compatible with a range of engines, including 2-stroke and 4-stroke, or diesel and gasoline engines, some cleaners could turn out incompatible with certain engines.

It's left for you to know what kind of engine or system that you're about to clean and to take a quick glance on the cleaner's manufacturer instructions, to make sure that it's compatible.

#2. Safety

A catalytic converter cleaner is a bottle filled with chemicals, so you need to know how safe it is to use in your car, as well as how safe it is for the environment if you're Eco-friendly.

You can confirm that the cleaner meets the necessary regulations like the VOC (Volatile Organic Compound) and OTC regulations, or others like the low-sulfur content requirements.

#3. Brand

Since it's a rather difficult task to try to guess beforehand, how effective a said cleaning additive is, the manufacturer's brand, however, can offer some help.

Some brands are better known than others, while even fewer brands of catalytic converter cleaner are well-known to work well. If you want to take the guesswork out, then go with a brand that you know it always delivers good results.

#4. Quantity & Price

You should keep in mind that a catalytic converter cleaning routine is not a one-off event, but is rather something you need to do from time to time.

So you may want to consider any packages that offer you a volume discount so you can save some money in the long run.

How to Use a Catalytic Converter Cleaner

Following is a simple 7-step guide to getting the best from your catalytic converter cleaner of choice. By following this guide, you'll be able to restore your vehicle to the best performance, as well as pass any emission tests.

Here are the steps:

#1. Check your Spark Plugs

You might wonder what spark plugs have to do with cleaning your vehicle's catalytic converter. The truth though, is that excessive carbon buildup on your converter is probably a sign that your vehicle is running rich.

By “running rich”, the fuel and air mixture is either not right, or one of your spark plugs isn't sparking correctly. It's a good idea to change your plugs from time to time, especially if you don't remember the last time you changed them.

Having good spark plugs helps to lower the rate of carbon build up on your catalytic converter by burning all the available fuel completely. You'll need to check your vehicle's manual to know the type and amount of plugs to buy.

#2. Empty the Bottle

Once you've dealt with your plugs and everything is okay, it's now time to empty the contents of the cleaner that you bought, into your vehicle's gas tank. Simply open the tank, open the bottle, and then empty it inside.

Always remember to read the instructions before using it. So, if your specific cleaner comes with any specific instructions for using it, then make sure you stick to its instructions.

#3. Fill the Tank

You should now fill your vehicle's tank until it's full or about 10 gallons.

#4. Drive Around till Empty

It's recommended that you drive around for at least 50 miles straight after the application to get the best results from the cleaning process. Ideally, you should drive the car until the tank is empty.

#5. Check Engine Light

Your car's check engine light should go off by now, else, feel free to repeat the process. If your vehicle alerted you to the catalytic cleaner's issue using error codes, now will be the time to clear these codes.

Since cars are different from each other, you may need to consult your vehicle owner's manual to see instructions on clearing the codes, or it could be automatic.

#6. Refill your Tank & That's It!

Refill your tank and carry on with your day-to-day activities, or go and test your car's emission levels. The cleanse should definitely be over by now.

Remember to cleanse your car again from time to time. The exact time-frame though depends on how often you use the vehicle. Once a year is okay for cars you seldom use, with up to 3-4 cleaning sessions per year for cars you use daily.


We have reached the end of this catalytic converter cleaner review and you have seen how easy it is to use a catalytic converter cleaner to unclog your exhaust system.

You've seen the different offers as well, including their unique features and volume discounts.

The final decision though remains yours to make. You can choose based on price, effectiveness, or volume. Just remember to follow the instructions to guarantee a successful system cleanse.

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