Best Catalytic Converter Cleaners: Clean Engines, Smooth Rides

Keep your engine high-performance ready with regular catalytic converter cleaning

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One of the most underappreciated components of a car, the catalytic converter works hard to filter out dangerous chemicals and compounds from exhaust gases. While doing its important work, the catalytic converter has a tendency to get gunked up, which means that it requires regular cleaning to function properly. Enter the catalytic converter cleaner. In this guide, you’ll learn everything you need to know to find the best catalytic converter cleaner for your needs

  • Best Overall
    Chevron Techron Concentrate Plus Fuel System Cleaner
    One of the top products on the market, this catalytic converter cleaner is concentrated to deliver super-charged results.
    Cleans, restores, and protects the entire fuel system; helps restore lost power and acceleration; improves fuel efficiency; smoothes idling and improved cold start performance.
    Inconvenient packaging. The foil that seals the cap is difficult to remove, leading to some frustration.
  • Best Value
    Marvel Mystery Oil Ultimate Fuel and Motor Treatment
    Excellent value product that packs a performance punch. If you’re looking for a great all-rounder, this might be the pick for you.
    Suitable for all engine types, including hybrids and diesel; prevents rust and corrosion from ethanol-containing fuels; and features top-end lubrication to restore engine power.
    Meant for cleaning the whole system, which lessens the cleaning effects on the converter itself.
  • Honorable Mention
    Red Line Complete SI-1 Fuel System Cleaner
    A concentrated fuel system cleaner, this restores engine efficiency with just one treatment in new and old cars.
    Formulation made for continual use; synthetic lubrication included in the formulation to help your engine run more smoothly; reduces carbon build-up in all engine parts, and helps clear up engine sounds.
    Packaging qualm: The nozzle on the bottle is too short to properly fit into some gas tanks, which can lead to spills.

Benefits of Catalytic Converter Cleaner

  • Lower emission levels. Modern catalytic converters already do pretty well to keep the number of harmful gases emitted from the car’s engine to a minimum. Adding a catalytic converter cleaner to the mix reduces the engine’s emission levels even further.
  • Better engine performance. Have you noticed less performance from your engine? A gunked up catalytic converter may be to blame. Using a catalytic converter cleaner regularly will help clean the fuel injection system, as well as the cylinders, improving overall performance while cutting down on fuel consumption.
  • Save money. Better engine performance has another benefit: It saves you money, thanks to lower maintenance and fuel costs. On top of that, you won’t have to shell out the big bucks to change your catalytic converter.
  • Reduce bad smells. Some cars develop an icky smell over time, caused by build-up in the catalytic converter. If your car has the signature rotten egg smell, a catalytic converter cleaner can help.
  • Protect your engine. Regularly cleaning out your catalytic converter has another big benefit: It’ll help protect your engine from damage. Proper fuel and exhaust flow will keep that engine running cleaner, smoother, and better, which will also cut down on maintenance costs.
  • Pass emission tests. If you’ve got an older vehicle and are up for an emissions test, a catalytic converter cleaning treatment can help. The formulation knocks old gunk, grime, and other carbon-based build-ups out of the fuel system, leading to cleaner emissions.

Top Brands

Red Line Oil

Headquartered in Benicia, California, Red Line Oil has been around for over 40 years. With roots in the racing industry, Red Line later expanded into the mainstream markets as manufacturers of high-quality engine lubricants. Since then, the company has expanded again into making a number of different automotive fluids, with the Complete SI-1 Fuel System Cleaner being among the most popular products.


Founded in 1879, Chevron is among the big names in the automotive and oil sectors. With headquarters in San Ramon, California, Chevron has been continuing to make high-quality automotive products, among which we find the most popular catalytic converter cleaner on the market, the Techron Concentrate Plus Fuel System Cleaner.

Royal Purple

Based in Porter, Texas, this automotive oil company prides itself in making high-quality engine oils and lubricants. With more than 200 years of collective experience in making high-performance lubricants and other automotive fluids, Royal Purple is a name you can trust. The company’s most popular product is the Max-Clean Fuel System Cleaner.

Catalytic Converter Cleaner Pricing

  • Under $10: Catalytic converter cleaner at this low price point is usually of the budget variety. You won’t get as good cleaning as from a mid-range or high-end brand, and you might accidentally get stuck with a knock-off that can do more harm than good.
  • $10 - $20: At this price point, you’re getting a good quality product that will get the job done. You’ll find a number of slightly different formulations that end up doing most of the same thing. Keep in mind that a diesel or hybrid car will need a different formulation, many of which can be found at the upper end of this price range.
  • Over $20: The high-end of catalytic converter cleaners consists of big name brands and multipacks. If you’re paying more than $20 for a single bottle, you could already be paying too much, unless it’s a specialty formulation.

Key Features

Engine Compatibility

For regular, gasoline-powered engines, almost all catalytic converter cleaning treatments will work with your vehicle. If you happen to drive a diesel or hybrid car, however, you should check the engine compatibility of the cleaner you’re considering. In most cases, a more premium blend is needed for this type of specialized engine.

Full System Cleaning

The best formulations out there are capable of cleaning the entire exhaust system, not just the catalytic converter. Since every part of the exhaust system is integral to how well the overall system functions, your catalytic converter cleaner should be able to give the whole thing a good flush. That will keep everything working in unison.

Multipack Options

Although the catalytic converter cleaner isn’t all that expensive, you’ll still want to make use of a great deal. This is where multipack options come in. They’re especially useful as you’ll need catalytic converter cleaner as a regular part of your car maintenance routine, saving you money in the long run.

Other Considerations

  • Additives: Some catalytic converter cleaners on the market include additional detergent additives that you don’t need in an effort to sell at a higher price point. If you’ve got a regular gas-powered car, you don’t need anything fancy to do the job right.
  • Bottle Size: Although not the most critical consideration, it’s still an important one. Catalytic converter cleaner comes in a number of bottle sizes, with 16 ounces being the most common. Anything bigger will be a waste, as the opened bottle will start to lose potency over time.
  • Formulation: The labeling of catalytic converter cleaner can be a little confusing since there are a number of look-alike products out there. Keep in mind that fuel treatments and stabilizers are not necessarily catalytic converter cleaners.

Best Catalytic Converter Cleaner Reviews & Recommendations 2019

Best Catalytic Converter Cleaner Overall: Chevron Techron Concentrate Plus Fuel System Cleaner

Chevron Techron Concentrate Plus Fuel System Cleaner

One of the most popular products on the market, the Chevron Techron catalytic converter cleaner works on multiple levels. It cleans, restores, and protects the entire fuel system, including the injectors, carburetors, intake valves, and combustion chambers. Through its unique formulation, it restores lost power and acceleration and helps boost fuel economy. If you’re having some troubles with the fuel gauge sensor, this product can help reset it.

For older cars, this product is especially helpful. It reduces rough idle and engine surge, as well as spark plug fouling, helping your engine run more smoothly in the process. If you live in colder areas, you’ll definitely benefit from the improved cold start performance and fuel stability this product provides. It’s suitable for all gasoline engines, including motorcycles, dirt bikes, boats, and lawnmowers.

Overall, this is one of the best catalytic converter cleaners out there, as it removes carbon build-up from the entire fuel system and the engine. Our one qualm with this product is the packaging. The foil that seals the cap is really hard to remove, making it a bit of a hassle to use. You also have to be careful not to drop any of the foil into your gas tank as you’re filling in the product.

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Best Value Catalytic Converter Cleaner: Marvel Mystery Oil Ultimate Fuel and Motor Treatment

Marvel Mystery Oil Ultimate Fuel and Motor Treatment

Although this brand has a quirky name, the product it delivers is no laughing stock. Not only is the price an excellent overall value, but it also packs a performance punch. Suitable for all engine types, including hybrids and diesel engines, this product removes up to 99 percent more catalytic converter deposits than gasoline alone. The formulation is specially made to prevent rust and corrosion from ethanol-containing fuels, which is a great benefit if you regularly use ethanol-containing gasoline.

Like its predecessor, this product also features top-end lubrication, which is essential for restoring engine power and fuel economy (it also makes for smoother idling). The long-lasting effect of this fuel and motor treatment also helps to keep fuel stabilized, promoting easy start-ups. If you have an older car that has trouble with carbon deposits in and around the fuel system and engine, this product has been known to help clear those up, saving you money at the mechanic’s garage.

It delivers great results at a great price point, which is tough to beat. However, if you’re looking for something that focuses more on the catalytic converter and less on the entire fuel system, you might want to look elsewhere. Keep in mind, though, that this product does clean out the converter as well.

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Best Catalytic Converter Cleaner Honorable Mention: Red Line Complete SI-1 Fuel System Cleaner

Red Line Complete SI-1 Fuel System Cleaner

As a concentrated fuel system cleaner, this Red Line SI-1 is powerful stuff. It cleans to nearly 100 percent efficiency in a single treatment, barring any major carbon build ups. The formulation is designed to reduce the need for octane by up to two points and is safe for continual use, making it perfect for regular car maintenance. One small bottle per tank of gas is an effective treatment for cleaning out gunk and grime from your vehicle’s catalytic converter and overall fuel system.

Another great benefit of this product is the included synthetic lubricant in the formulation, which coats the upper cylinders. This helps your engine run more smoothly. As part of a regular maintenance program, this product helps keep your intake manifold and throttle body free of carbon build-up, reducing wear on the engine’s parts. If you’ve got an older car that has a ping in the engine, this product has been known to help clear that up as well.

Overall, this is a great product that delivers consistent results. The only thing we were disappointed with is the short nozzle tip of the packaging, which can make it a little difficult to fill into some gas tanks. This mostly affects big SUVs and trucks, though, so you should be good to go with smaller vehicles. A funnel can help keep the pour drip-free as well.

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  • As a general rule of thumb, you’ll want to use about one ounce of catalytic converter cleaner to one gallon of fuel. This formula makes it easy to adjust the amount you need for smaller engines, including motorcycles.
  • You don’t need to have a full tank of gas to use a catalytic converter cleaner. The more important step is to use up as much of the tank as possible with the converter cleaner in it to maximize its cleaning potential.
  • Older cars may benefit from more frequent catalytic converter cleaner use, as these tend to produce more harmful emissions than newer vehicles.
  • After using catalytic converter cleaner, fill up your gas tank completely and drive about 50 miles on highways and side streets to re-calibrate your onboard computer. This step can help clear up oxygen sensor issues, among other things.
  • If you’ve never used a catalytic converter cleaner before, and you’ve already driven thousands of miles, start sooner rather than later with regular catalytic converter maintenance to help reduce the chance of trouble down the line.
Hands of a mechanic visible in the process of changing an old catalytic converter with rusted parts

Help prevent a costly catalytic converter replacement by keeping your fuel system clean and well-maintained


Q: How do I use a catalytic converter cleaner?

A: Using a catalytic converter cleaner is one of the simplest routine maintenance tasks you can perform. One 16-ounce bottle is enough to clean up a couple of thousand miles worth of gunk. Simply pour it into your semi-full gas tank and drive on that tank until it’s almost empty to make sure that most of the chemical cleaner is used up.

Q: Can I use a catalytic converter cleaner to fix a clogged catalytic converter?

A: Unfortunately, catalytic converter cleaner is not a mechanic-in-a-bottle and won’t be the end-all, fix-all to your engine troubles. If your catalytic converter is truly clogged, the only way to fix the problem is to replace the converter.

Q: How does a catalytic converter cleaner work?

A: Catalytic converters do their job by filtering out and converting harmful compounds and gases in the exhaust into less harmful ones, like carbon dioxide and nitrogen. In this process, gunk can start accumulating in your catalytic converter, most of which will be carbon. A catalytic converter cleaner is a liquid chemical formulation that runs through your converter, dissolving the build-up via chemical reactions.

Q: How often can I use a catalytic converter cleaner?

A: The catalytic converter is one of the most overlooked car parts, often only getting cleaned after many thousands of miles. To get the best results from both your cleaner and your car, you should consider cleaning the catalytic converter every 4,000 miles or so.

Q: Do catalytic converter cleaners work in all car makes and models?

A: Catalytic converter cleaners are safe to use with all car makes and models, including older cars. However, if you drive a diesel or hybrid vehicle, you’ll want to make sure the cleaner you buy is compatible with your engine. How well they work depends on a couple of factors, but mainly on how much grime has accumulated within your converter. The more dirt, the fewer results. Make sure to clean your catalytic converter regularly.

Final Thoughts

Our top pick for the best catalytic converter cleaner out there is the Chevron Techron Concentrate Plus Fuel System Cleaner. It delivers consistently great results that help your engine run better.

If you’re looking for a great value, check out the Marvel Mystery Oil Ultimate Fuel and Motor Treatment. With results rivaling some of the more expensive catalytic converter cleaners out there, it’s a solid choice.

What do you think of our picks? Do you have a favorite catalytic converter cleaner? Let us know your thoughts in the comments below!