This article was updated in January 18, 2026 with new products and information by Mark S. Taylor
Is your car loud or slow? The best catalytic converter cleaner can help fix it. Over time, your exhaust pipes get clogged with dirt. This hurts your engine and hurts the air. We have tested many options to help you choose. In this guide, you will find top products and easy tips. Read on to get your car running right.
Contents
What Is a Catalytic Converter Cleaner?
It is a special liquid you add to your gas tank.
A catalytic converter cleaner removes carbon from your car’s exhaust system. It uses strong chemicals to break down dirt. When your engine runs, the fluid passes through hot parts. It cleans the metal inside the pipes. This helps air flow better.
Why do these parts get dirty? Old cars or bad gas leave behind carbon deposits. Fuel wash can also clog the system. Imagine a water pipe with mud inside. The water flows slow. Your car acts the same way when the exhaust is blocked. For example, a high-mile car may feel weak on hills. A cleaner helps clear that path.
Liqui Moly Catalytic System Clean
The Liqui Moly Catalytic System Clean 300 ml 7110 is ideal for car owners and automotive enthusiasts who want to maintain optimal engine performance and reduce harmful emissions. This product is perfect for those who frequently drive in urban environments or experience engine knocking and rough idling due to carbon buildup in the injection system and combustion chamber. If you seek an effective and easy-to-use solution to keep your engine clean and efficient, this catalytic system cleaner is a must-have.
Pros:
- Effectively cleans the injection system and combustion chamber to improve engine performance.
- Reduces harmful emissions, contributing to a cleaner environment.
- Easy to use with a compact 300 ml bottle size.
- Made by Liqui Moly, a trusted and reputable brand in automotive care.
- Helps restore engine smoothness and fuel efficiency.
Cons:
- May require multiple treatments for heavily carboned engines.
- Limited bottle size may not be sufficient for larger engines or frequent use.
The Liqui Moly Catalytic System Clean 300 ml 7110 is designed to penetrate and dissolve deposits in the injection system and combustion chamber, which can accumulate over time and impair engine function. By targeting these critical areas, the product helps restore proper fuel atomization and combustion, leading to smoother engine operation and reduced knocking. The compact dimensions (Height: 7.28 inches, Width: 2.13 inches, Length: 2.13 inches) and lightweight design make it easy to handle and store in your garage or vehicle.
Using this cleaner regularly can enhance your vehicle’s fuel economy by ensuring that fuel is burned more efficiently, which also lowers pollutant emissions. The product’s formulation is compatible with various fuel types and engine models, making it a versatile choice for many drivers. Overall, the Liqui Moly Catalytic System Clean is an excellent investment for those who want to maintain engine health, improve performance, and contribute to environmental protection.
Cataclean Fuel & Exhaust System Cleaner
The Cataclean Fuel & Exhaust System Cleaner is ideal for vehicle owners looking to improve their car’s performance, pass emissions tests, and maintain the health of their engine. Whether you drive a gasoline or diesel engine, this product is perfect for those who want to clear check engine lights, restore catalytic converters and DPF filters, and keep their fuel systems clean and efficient. It is especially useful for people experiencing rough idling, decreased fuel economy, or failed emissions tests.
Pros:
- Effectively restores catalytic converters and DPF filters
- Helps pass strict emissions tests
- Clears annoying check engine lights
- Compatible with both gasoline and diesel engines
- Easy to use with a 16oz pack size and comes in a convenient pack of 2
Cons:
- May require multiple uses for heavily clogged systems
- Only suitable for regular maintenance, not for severe engine damage
The Cataclean Fuel & Exhaust System Cleaner is designed with advanced chemical formulations that target deposits in the fuel system and exhaust components. By dissolving harmful carbon buildup, it helps restore the efficiency of the catalytic converter and DPF filter, which are essential for reducing vehicle emissions. This leads to a smoother running engine, improved fuel economy, and a significant reduction in exhaust pollutants.
Additionally, the product’s ability to clear check engine lights provides users with peace of mind and avoids unnecessary visits to the mechanic. Its user-friendly application and compatibility with various engine types make it a versatile solution for ongoing vehicle maintenance. Regular use can extend the life of critical engine components and ensure your vehicle meets environmental standards with ease.
Cataclean Fuel & Exhaust System Cleaner
The Cataclean Fuel & Exhaust System Cleaner is ideal for vehicle owners who want to maintain optimal engine performance and pass emissions tests without costly repairs. It is perfect for those experiencing issues like a persistent check engine light, decreased fuel efficiency, or concerns about their catalytic converter and DPF filter health. Whether you own a gasoline or diesel vehicle, this cleaner helps restore and maintain your exhaust system’s efficiency.
Pros:
- Effectively passes emissions tests by cleaning exhaust components
- Helps clear check engine lights related to fuel and exhaust issues
- Restores the functionality of catalytic converters and DPF filters
- Cleans the entire fuel system to improve engine performance
- Easy to use 16oz bottle suitable for multiple treatments
- Manufactured by reliable brand Mr. Gasket Co.
Cons:
- Results may vary depending on the severity of engine problems
- Requires regular use to maintain benefits
- Not a substitute for mechanical repairs when parts are severely damaged
The Cataclean Fuel & Exhaust System Cleaner features a unique formula designed to safely dissolve and remove harmful deposits from your vehicle’s fuel system and exhaust components. This leads to improved combustion efficiency, reduced emissions, and better fuel economy. Its ability to restore the catalytic converter and diesel particulate filter (DPF) extends the life of these expensive components, reducing the need for costly replacements. The product’s 16oz size allows for convenient dosing, making it suitable for multiple applications depending on your vehicle’s requirements.
By regularly using this cleaner, users benefit from a cleaner engine environment which can result in smoother idling, improved throttle response, and fewer engine warning lights. Additionally, the reduction in harmful emissions helps your vehicle stay compliant with environmental regulations, making it an excellent choice for eco-conscious drivers. Overall, the Cataclean Fuel & Exhaust System Cleaner offers a practical and cost-effective solution for those seeking to maintain their vehicle’s performance and reduce emissions without extensive mechanical work.
Catalytic Converter Cleaner
The 2X Cans Catalytic Converter Cleaner by MotorPower Care is ideal for vehicle owners who are looking to maintain or improve their car’s emission system performance. If you want to pass emissions tests with ease, reduce smog, and enhance fuel efficiency, this product is designed for you. It is particularly useful for those who notice reduced engine performance or increased exhaust emissions and want a simple solution to clean their catalytic converter and oxygen sensors.
Pros:
- Effectively cleans catalytic converters and oxygen sensors to improve vehicle emissions
- Helps pass smog and emissions tests by reducing harmful exhaust gases
- Acts as a fuel additive and combustion chamber cleaner, enhancing engine performance
- Easy to use with two cans for extended treatment or multiple uses
- Manufactured by MotorPower Care, ensuring quality and reliability
Cons:
- Limited weight of 1.34 pounds may require multiple treatments for heavily clogged systems
- May not be suitable for all vehicle types without checking compatibility
The 2X Cans Catalytic Converter Cleaner works by breaking down carbon deposits and contaminants that accumulate in the catalytic converter and oxygen sensors. This cleaning process helps restore the efficiency of the emission control system, leading to a cleaner exhaust output and better engine response. By using this cleaner, users can expect smoother engine operation and potentially improved fuel economy as the combustion chamber is also treated to remove buildup.
Additionally, the product’s formulation is designed to be safe for use with various fuel types and emission systems, making it a versatile choice for many vehicles. Regular use can extend the life of critical engine components and reduce costly repairs related to emissions failures. Overall, this cleaner offers a practical and effective solution for maintaining vehicle emissions and promoting environmental responsibility.
Bluedevil Complete Catalytic & Emissions Cleaner
The BlueDevil 70523 Complete Catalytic & Emissions Cleaner is ideal for vehicle owners who want to improve their car’s emission system performance and reduce harmful exhaust pollutants. If you are looking for an effective solution to maintain your vehicle’s catalytic converter and overall emissions system, this product is designed specifically for you. It is perfect for those who want an easy-to-use, preventive maintenance product to keep their engine running cleaner and greener.
Pros:
- Effectively cleans the catalytic converter and emissions system
- Helps reduce harmful exhaust emissions and improve air quality
- Easy to use with simple bottle addition to the fuel tank
- Compatible with most gasoline engines
- Manufactured by BlueDevil Products, a trusted brand for automotive solutions
Cons:
- May require multiple treatments for heavily clogged systems
- Not suitable for diesel engines
- Results may vary depending on vehicle condition and usage
The BlueDevil 70523 Complete Catalytic & Emissions Cleaner is formulated to break down carbon deposits and other contaminants that build up in the catalytic converter and other emission control components. By adding this cleaner to your fuel tank, it works during normal driving to restore the efficiency of your vehicle’s emissions system. This helps your car meet emission standards while also potentially improving fuel efficiency and engine performance.
This product offers a convenient and cost-effective way to maintain your vehicle’s emission system without the need for expensive repairs or replacements. With consistent use, it helps extend the life of the catalytic converter and reduces the risk of costly emission-related problems. BlueDevil’s proven formula ensures that your car runs cleaner, contributing to a healthier environment and a smoother driving experience.
How to Tell if You Need a Cleaner
Look for warning signs before you buy.
The most common sign is the Check Engine Light. This light can mean many things. You should use a scanner to check the code. Code P0420 usually means the converter is bad. It means the system is not efficient.
You might also smell bad fumes. A clogged converter makes a rotten egg smell. This comes from sulfur in the gas. If the smell is strong, check the exhaust soon. A check engine light is a clear cry for help.
Signs You Need a Catalytic Converter Cleaner
Your car will show you specific symptoms.
If your engine stalls or lacks power, the pipe might be blocked. The engine cannot breathe out. Fresh air cannot get in. This makes the car feel weak.
A Check Engine Light for emissions is a big clue. Sensors detect too much pollution. They tell the computer to turn on the light. Do not ignore this warning.
Poor fuel economy is another sign. You will buy gas more often. The engine works harder to push air out. This wastes fuel and your money.
Reduced exhaust flow happens slowly. You might notice less pressure from the tailpipe. Put your hand near the pipe (carefully). If the flow feels weak, you may have a clog.
How Catalytic Converter Cleaners Work
They use chemicals to clean while you drive.
Additives go into your fuel and help dissolve deposits. These additives are solvents. They are like soap for your engine. When gas burns, the cleaner goes through the exhaust. It coats the internal parts. It eats away at the carbon buildup.
Simple spray-in options exist for gas tanks too. You just pour the bottle in. You do not need to take parts apart. This makes it an easy fix for most people.
There are limitations to these products. Very clogged units may need pro cleaning. If the metal inside is broken, fluid cannot fix it. If the core is melted, you must replace the part. A cleaner is for dirty parts, not broken ones.
How to Use a Catalytic Converter Cleaner
Follow these steps for the best results.
First, add to fuel tank at fill-up. Do not add to a full tank. It is best to add when the tank is low. Then, fill the tank up with gas. This mixes the cleaner well.
Next, run the engine at highway speed. The cleaner needs heat to work. Drive on the freeway for 20 to 30 minutes. This keeps the engine hot. The heat activates the chemicals.
Repeat if needed per product instructions. Some bad clogs need two treatments. Wait a few days between uses. Check your fluid levels too. If the light stays on, you may need a mechanic. You can learn more about car maintenance tips on our blog.
When Cleaning Works vs When to Replace
Cleaning is good for mild clogging.
If your car has high mileage, cleaning helps. It restores flow and clears codes. It is much cheaper than a new part. A cleaner costs about $20. A new part costs over $1,000.
It is not a fix for broken bricks inside the converter. If you hear rattling, the part is broken. If the car will not start, the part is plugged solid. Fluid cannot fix physical damage.
If codes persist, see a mechanic. A professional can test the sensors. They can check the oxygen sensors too. Sometimes the sensor is the problem, not the pipe. Replacing a sensor is cheap. Replacing the whole unit is expensive. For more on how sensors work, check out this resource on oxygen sensors.
Buyer Guide — What to Look For
Choose the right product for your car.
Look for EPA-approved formulas. This means it is safe for the environment. It also means it is safe for your car. Avoid harsh chemicals that can hurt rubber seals.
Brand reliability matters a lot. Big brands test their products. Brands like Cataclean or CRC are well known. They have good reviews. Stick to names you trust.
Check the amount per tank. Some bottles treat 5 gallons. Some treat 20 gallons. Make sure you buy enough for your car. Read the label on the back.
Ensure it is safe for oxygen sensors. The cleaner flows past the sensors. Cheap cleaners can coat the sensors. This makes them fail. A failed sensor gives a false code.
Top Product Features to Compare:
Liqui Moly: Best choice for diesel trucks.
Cataclean: Good for overall system cleaning.
Solder-It: Great for small budgets.
CRC: Works well for high mileage cars.
FAQ About Best Catalytic Converter Cleaner
What is the most effective catalytic converter cleaner?
Many experts rank Cataclean as the top choice. It cleans the whole fuel system.
Do catalytic converter cleaners actually work?
Yes, they work for carbon buildup. They do not fix broken physical parts.
How long does it take for Cataclean to work?
It usually works within one tank of gas. You should drive about 50 miles to see results.
How to clean a car catalytic converter without removing it?
Pour a cleaner into the gas tank. Drive on the highway for 20 minutes to heat it up.
Will a converter cleaner fix a blocked converter?
No. If it is fully blocked, the cleaner cannot pass through. You must replace it.
Verdict / Bottom Line
Use a cleaner to save money and time.
The best catalytic converter cleaner removes carbon deposits. It helps your car run better. It is cheap and easy to use. Try a cleaner if you have a Check Engine Light. It might clear the code. If the car is damaged, buy a new part. Fix small issues now to avoid big bills later.
Quick Summary
- Check the Code: Use a scanner to see if P0420 is the issue.
- Try a Cleaner: Add a product like Cataclean to your gas tank.
- Drive It: Drive on the highway to heat up the exhaust.
- Check Limits: Cleaners fix dirt, not broken metal parts.
- Replace if Needed: If it rattles or stays clogged, get a new one.
- Sensors Matter: Ensure the cleaner is safe for oxygen sensors.
- Save Cash: A $20 bottle is cheaper than a mechanic visit.