We researched and compared the leading gasoline catalytic converter cleaners using manufacturer specifications, industry standards, and aggregated owner feedback. Our evaluation focuses on how effectively each product removes carbon deposits from the catalytic converter and oxygen sensors, improving engine performance and reducing emissions. We also considered ease of use, compatibility with various fuel systems, and potential risks. Below are our findings to help you choose the right cleaner for your vehicle.
| Photo | Product | Score | Buy |
|---|---|---|---|
 |
Cataclean Catalytic Converter Cleaner Best Overall 1200120 formula, treats up to 20 gallons |
9.0 | 🛒 Check Price |
 |
Lucas Oil 10013 Catalytic Converter Cleaner Best Value 16 oz bottle, treats 15-25 gallons |
8.6 | 🛒 Check Price |
 |
CRC Guaranteed To Pass Emissions Formula Emissions Specialist 16 oz, treats 12-20 gallons |
8.4 | 🛒 Check Price |
 |
STP Catalytic Converter Cleaner Trusted Brand 5.25 oz concentrate, treats up to 20 gallons |
8.1 | 🛒 Check Price |
|
🚗
|
Rislone 4450 Catalytic Converter Cleaner High Mileage Formula 16 oz, treats 15-25 gallons |
7.8 | 🛒 Check Price |
 |
Liqui Moly Catalytic Converter Cleaner German Engineering 300 ml can, treats up to 20 gallons |
7.5 | 🛒 Check Price |
 |
Berryman 0116 Catalytic Converter Cleaner Budget Pick 16 oz, treats 15-20 gallons |
7.2 | 🛒 Check Price |
1. Cataclean Catalytic Converter Cleaner: Best Overall
Cataclean is a top-rated catalytic converter cleaner that we found consistently delivers on its promises based on owner feedback and spec sheet analysis. It uses a proprietary blend of detergents and solvents to break down carbon deposits in the converter, oxygen sensors, and fuel system. Users report noticeable improvements in acceleration and reduced check engine light illumination related to catalytic converter efficiency codes. The formula is safe for all gasoline engines and does not harm O2 sensors.
However, for optimal results, Cataclean requires a near-empty tank and a full treatment cycle including highway driving. It may not fully resolve severely clogged or damaged converters. Those with heavily fouled systems might need professional cleaning or replacement. Additionally, it is not recommended for vehicles with less than 10 gallons of fuel capacity.
- Formulated to clean catalytic converters, oxygen sensors, and fuel injectors
- Works with gasoline and diesel engines (gasoline variant available)
- Safe for all OBDII and OBDI systems
Pros: Widely praised for restoring lost power and fuel economy; Easy pour-in application, no special tools required
Cons: May require a full tank and highway driving for best results
2. Lucas Oil 10013 Catalytic Converter Cleaner: Best Value
Lucas Oil’s catalytic converter cleaner is a cost-effective solution that we evaluated as a solid choice for routine maintenance. It combines their famous fuel system cleaner with additional agents targeting converter deposits. Owner reviews frequently mention smoother idling and improved throttle response after use. The formula is compatible with all gasoline blends and does not contain harsh chemicals that could damage seals.
However, for heavily clogged converters, this cleaner may not be strong enough on its own. Some users with persistent P0420 codes found it only temporarily resolved the issue. It is best used as a preventive measure rather than a cure for severe problems. Those with advanced converter failure should consider professional diagnosis.
- Blend of high-detergency oils and solvents
- Safe for all gasoline engines including turbo and supercharged
- Also cleans fuel injectors and intake valves
Pros: Affordable and widely available; Reduces emissions and improves fuel economy
Cons: May require multiple treatments for severe buildup
3. CRC Guaranteed To Pass Emissions Formula: Emissions Specialist
CRC’s Guaranteed To Pass Emissions Formula is a specialized cleaner we reviewed for its focus on emission system cleaning. It is formulated to reduce hydrocarbon and NOx emissions by cleaning the catalytic converter, oxygen sensors, and fuel system. Owner feedback indicates it is effective at resolving emission test failures related to converter inefficiency. The product is easy to use and requires no special equipment.
That said, this cleaner is not a cure-all for physically damaged converters or extremely heavy carbon buildup. It works best when used before an emissions test as a last-minute cleaning. Some users found it did not resolve persistent check engine lights for P0420 codes. For severe cases, a more aggressive cleaner or converter replacement may be needed.
- Specifically designed to help vehicles pass emissions tests
- Contains oxygen sensor safe cleaner
- Works with all gasoline engines including hybrid
Pros: Targeted formula for emission-related issues; Backed by a satisfaction guarantee
Cons: Not intended for severe catalytic converter clogging
4. STP Catalytic Converter Cleaner: Trusted Brand
STP’s catalytic converter cleaner is a concentrate that we found offers good value for its price. It is designed to remove carbon deposits from the converter and fuel system. Many owners report it helps with rough idle and hesitation. The small bottle is easy to store and pour.
However, in our evaluation of owner feedback, some users did not see significant improvements in check engine light codes. The cleaner may not be potent enough for converters with years of buildup. It is best suited for light to moderate maintenance. Those with severe converter issues should look at stronger options like Cataclean.
- Concentrated formula for maximum cleaning
- Safe for all gasoline engines and fuel injection systems
- Helps reduce emissions and restore fuel economy
Pros: Small bottle treats a full tank; Trusted brand with decades of history
Cons: Some users report mixed results on heavy buildup
5. Rislone 4450 Catalytic Converter Cleaner: High Mileage Formula
Rislone 4450 is a catalytic converter cleaner we evaluated that is specifically marketed for high-mileage vehicles. It includes seal conditioners to help prevent leaks in older engines. Owner reviews from high-mileage drivers note improved performance and reduced smoke. The formula is gentle on engine components.
However, for newer vehicles or those with low mileage, the seal conditioners are unnecessary and may not provide the same cleaning power as dedicated converter cleaners. Additionally, some users with severe converter clogging found it insufficient. It is best for older cars with moderate carbon buildup.
- Formulated for high-mileage vehicles
- Contains seal conditioners and detergents
- Safe for gasoline and flex-fuel engines
Pros: Adds lubricity to fuel system seals; Helps reduce emissions in older cars
Cons: May not be effective on modern low-mileage engines
6. Liqui Moly Catalytic Converter Cleaner: German Engineering
Liqui Moly’s catalytic converter cleaner is a premium product we examined for its German engineering. It is designed to clean the entire exhaust system including the converter. Owner reviews from European car owners are positive, noting restored performance. The canister is easy to use and includes a measuring guide.
However, the cost per treatment is higher than many alternatives, and it may not be as readily available in North America. Some users felt it did not outperform cheaper options for heavy buildup. It is best for those who prefer a trusted European brand and have light maintenance needs.
- German-made high-performance cleaner
- Reduces emissions and improves exhaust flow
- Safe for catalytic converters and oxygen sensors
Pros: Premium brand known for quality additives; Effective on light to moderate deposits
Cons: Higher price per treatment compared to competitors; Limited availability in some regions
7. Berryman 0116 Catalytic Converter Cleaner: Budget Pick
Berryman 0116 is a budget-friendly catalytic converter cleaner we reviewed that offers strong cleaning power. It contains solvents that effectively dissolve carbon deposits. Some owners report success in clearing P0420 codes. The price is appealing for those on a tight budget.
However, the strong chemical smell requires good ventilation during use, and there are reports of potential damage to oxygen sensors if overused. It may be too aggressive for some engines. We recommend it only for heavy buildup where other cleaners have failed, and with caution. Those with newer vehicles or sensitive emissions systems should choose a safer option.
- Strong solvent-based formula
- Works as fuel system cleaner and converter cleaner
- Safe for gasoline engines with OBDII systems
Pros: Very affordable price point; Can be used as a general fuel system cleaner
Cons: Harsh smell and may require ventilation; Not recommended for sensitive O2 sensors
Frequently Asked Questions
How does a catalytic converter cleaner work?
Catalytic converter cleaners contain detergents and solvents that are added to the fuel tank. As the fuel burns, the chemicals pass through the exhaust system and break down carbon deposits on the catalytic converter and oxygen sensors. This restores proper exhaust flow and efficiency, often reducing emissions and improving engine performance.
Will a catalytic converter cleaner fix a P0420 code?
It can, but only if the code is caused by carbon buildup rather than physical damage or contamination. Many owners have successfully cleared P0420 codes using a quality cleaner, especially when combined with a highway drive. However, if the converter is physically clogged or failed, replacement may be necessary.
How often should I use a catalytic converter cleaner?
Most manufacturers recommend using it every 10,000 to 15,000 miles as preventive maintenance. If you notice symptoms like reduced fuel economy or a check engine light, you can use it sooner. Overuse is not harmful, but unnecessary treatments may be a waste of product.
Can I use a catalytic converter cleaner in any gasoline engine?
Most cleaners are safe for all gasoline engines, including those with turbochargers, superchargers, and hybrid systems. Always check the label for compatibility. Some products are not recommended for diesel engines unless specified.
Are there any risks to using a catalytic converter cleaner?
When used as directed, risks are minimal. However, overuse or using a harsh solvent-based cleaner can damage oxygen sensors or seals. Always follow the instructions and avoid using in a nearly empty tank to prevent concentrated exposure.
Our Verdict
After researching and comparing these products, our top pick is Cataclean Catalytic Converter Cleaner for its proven performance and owner satisfaction. It effectively cleans converters and oxygen sensors, making it a reliable choice for most gasoline vehicles. For a budget-friendly option that still delivers good results, we recommend Lucas Oil 10013, especially for routine maintenance.
More Car Detailing Guides
Video Guide
Video: Related tutorial from YouTube