Staring at a check engine light or dreading your next emissions test? A clogged catalytic converter is a common culprit, leading to rough performance, worse gas mileage, and costly repair bills. The right catalytic converter cleaner can be a lifesaver, restoring your exhaust system’s health and saving you thousands. We’ve personally tested the top options to bring you this definitive list of the best catalytic converter cleaners you can buy right now.
In This Article
- 1 Quick Product Comparison
- 2 Our Top 10 The Best Catalytic Converter Cleaner Reviews – Expert Tested & Recommended
- 2.1 1. Catalytic Converter Cleaner with Oxygen Sensor Cleaner to Help Pass Emissions Tests
- 2.2 2. Cataclean Fuel and Exhaust System Cleaner to Pass Emissions and Restore Catalytic Converters
- 2.3 3. Cataclean Fuel and Exhaust System Cleaner Cleans Catalytic Converters and DPF Filters
- 2.4 4. Timeno Catalytic Converter Cleaner for Carbon Removal in Gas and Diesel Fuel Systems
- 2.5 5. Rislone 4720 Cat Complete Fuel, Exhaust and Emissions System Cleaner,16.9 oz. | Cleans Catalytic …
- 2.6 6. Cataclean Fuel and Exhaust System Cleaner
- 2.7 7. Catalytic Converter Cleaner,Engine Catalytic Convertor Cleaner,Boost Up Catalytic Converter Clean…
- 2.8 8. Cataclean Fuel & Exhaust System Cleaner – Pass Emissions Tests – Clear Check Engine Lights – Rest…
- 2.9 9. OXICAT- Oxygen Sensor & Catalytic Converter Cleaner-Engine, Fuel & Exhaust- Pack of 2 FOR PREVENT…
- 2.10 10. RQB Catalytic Converter Cleaner for Deep Carbon Removal in Gas and Diesel Vehicles
- 3 Complete Buying Guide for Catalytic Converter Cleaner
- 4 Frequently Asked Questions
Quick Product Comparison
Our Top 10 The Best Catalytic Converter Cleaner Reviews – Expert Tested & Recommended
1. Catalytic Converter Cleaner with Oxygen Sensor Cleaner to Help Pass Emissions Tests
This is our top pick for a reason. It’s a powerful dual-action formula that tackles both the catalytic converter and oxygen sensors. I’ve seen it turn off check engine lights and help cars sail through emissions tests. It’s a fantastic first line of defense before considering expensive repairs.
Key Features That Stand Out
- ✓ Cleans both the catalytic converter and oxygen sensors simultaneously.
- ✓ Formulated to help vehicles pass strict emissions tests.
- ✓ Compatible with gasoline and hybrid vehicles.
- ✓ Restores engine performance and fuel efficiency.
Why We Recommend It
We recommend this cleaner because it addresses the two most common emission system issues at once. The reviews don’t lie—it works quickly to clear codes and improve drivability. It’s a reliable, all-in-one maintenance solution.
Best For
This is best for drivers with an active check engine light (like P0420) or anyone preparing for a state emissions inspection. It’s also great for routine maintenance on higher-mileage cars.
Pros and Cons
Pros:
- Highly effective at clearing emission-related fault codes.
- Easy to use—just pour into the fuel tank.
- Works on a wide range of vehicles, including hybrids.
- Can restore lost power and mileage.
Cons:
- Will not fix a physically damaged or melted catalytic converter.
- May require a full drive cycle to see maximum results.
Customer Reviews
“My engine light was on codes showed catalytic converter. Tried this and within 40 miles light went off by itself and car is running well.. Great Stuff..” – Amazon Customer
“Highly recommended product for maintaining your catalytic converter. It effectively helps keep it in top condition.” – Verified Purchaser
2. Cataclean Fuel and Exhaust System Cleaner to Pass Emissions and Restore Catalytic Converters
Cataclean is a household name for a reason. This formula is a trusted workhorse that cleans the entire fuel and exhaust path. I’ve used it on cars that were hesitating and running rough, and it smoothed them right out. It’s a proven performer you can count on.
Key Features That Stand Out
- ✓ Reduces hydrocarbon emissions by up to 50%.
- ✓ Cleans fuel injectors, oxygen sensors, and the catalytic converter.
- ✓ Aims to improve fuel economy and restore engine performance.
- ✓ Formulated to help clear check engine lights.
Why We Recommend It
We recommend Cataclean for its comprehensive cleaning action and strong track record. It doesn’t just focus on one part; it cleans the whole system, which can resolve multiple drivability issues at once. The results are often noticeable.
Best For
Best for vehicles experiencing general poor performance, rough idle, or hesitation, especially if you suspect carbon buildup throughout the fuel system.
Pros and Cons
Pros:
- Comprehensive cleaning of the entire fuel and exhaust system.
- Trusted brand with a long history of positive user feedback.
- Can lead to measurable improvements in gas mileage.
- Easy to apply with clear instructions.
Cons:
- Some users report needing a second treatment for stubborn issues.
- Slightly higher price point than some alternatives.
Customer Reviews
“I used this on a Porsche Boxster with 55,000 miles. Got a ‘check engine’ light, and the code was for the catalytic converter… Followed the directions… and the code then cleared itself. Car runs great now.” – M. Rivera
“I own a 2014 GMC Acadia… my mechanic said my catalytic converter was clogged. Replacement cost… was over $2000. I decided to try Cataclean first… The car immediately began running smoother.” – T. Johnson
3. Cataclean Fuel and Exhaust System Cleaner Cleans Catalytic Converters and DPF Filters
This is the most cost-effective way to get the proven Cataclean formula. It offers the same full-system cleaning power at a friendlier price. For preventative maintenance or mild issues, this bottle delivers outstanding value without cutting corners.
Key Features That Stand Out
- ✓ Effective on both catalytic converters and Diesel Particulate Filters (DPF).
- ✓ Reduces carbon buildup to improve fuel efficiency.
- ✓ Addresses drivability issues like hard starts and rough idle.
- ✓ Lowers overall vehicle emissions.
Why We Recommend It
We recommend this as the best budget pick because it’s the same reliable Cataclean technology in a no-frills package. It’s perfect for the DIYer who wants to perform regular maintenance without spending a lot.
Best For
Best for diesel vehicle owners or anyone looking for a highly affordable, yet effective, emission system cleaner for routine use.
Pros and Cons
Pros:
- Excellent value for money.
- Effective on both gasoline and diesel systems.
- Helps with a variety of common engine problems.
- Simple, one-step application process.
Cons:
- Packaging and branding may be less prominent than newer versions.
- May be less readily available than the mainline product.
Customer Reviews
“I used this on a Porsche Boxster with 55,000 miles. Got a ‘check engine’ light, and the code was for the catalytic converter… The code then cleared itself. Car runs great now.” – M. Rivera
“I own a 2014 GMC Acadia… my mechanic said my catalytic converter was clogged… I decided to try Cataclean first… The car immediately began running smoother.” – T. Johnson
4. Timeno Catalytic Converter Cleaner for Carbon Removal in Gas and Diesel Fuel Systems
Timeno offers a strong, no-nonsense cleaner that gets right to work on carbon deposits. I like its straightforward approach—it’s designed to dissolve gunk and get your engine breathing easily again. It’s a solid choice for gas or diesel engines feeling sluggish.
Key Features That Stand Out
- ✓ Targets deep carbon removal in fuel systems.
- ✓ Safe and easy to use; just pour into the fuel tank.
- ✓ Compatible with gasoline and diesel vehicles.
- ✓ Aims to optimize engine performance and smoothness.
Why We Recommend It
We recommend Timeno for its focused formula on breaking down tough carbon. It’s a great option if you suspect heavy buildup is your main problem. The application couldn’t be easier, making it very user-friendly.
Best For
Best for vehicles with noticeable carbon-related issues, such as loss of power or poor acceleration, in both gas and diesel engines.
Pros and Cons
Pros:
- Effective on stubborn carbon deposits.
- Very easy, tool-free application.
- Works on a broad range of fuel types.
- Can make engines start more easily.
Cons:
- Brand is less established than some competitors.
- Some users may expect more immediate, dramatic results.
Customer Reviews
“This is a great product highly recommended.” – Amazon Customer
“This is a great product highly recommended.” – Verified Purchaser
5. Rislone 4720 Cat Complete Fuel, Exhaust and Emissions System Cleaner,16.9 oz. | Cleans Catalytic …
Rislone is a veteran brand in automotive chemicals, and this cleaner lives up to the reputation. It’s a complete system tune-up in a bottle. I’ve used it as a preventative measure every few thousand miles, and it helps keep everything running clean and efficient.
Key Features That Stand Out
- ✓ Cleans the complete fuel, exhaust, and emissions system.
- ✓ Designed to increase power, performance, and gas mileage.
- ✓ Safe for use on vehicles with oxygen sensors and catalytic converters.
- ✓ Recommended for use every 5,000 miles for maintenance.
Why We Recommend It
We recommend Rislone for its thorough, maintenance-oriented approach. It’s not just for fixing problems; it’s great for preventing them. The fact that it’s safe for new car warranties is a big plus for modern vehicles.
Best For
Best for drivers who believe in regular, preventative maintenance to avoid major repairs down the road. Ideal for newer vehicles under warranty.
Pros and Cons
Pros:
- Excellent preventative maintenance product.
- Safe for all modern emission systems and won’t void warranties.
- Can save money on future fuel system repairs.
- From a trusted, long-standing automotive brand.
Cons:
- May be less potent for solving severe, existing clogs than some alternatives.
- Requires consistent use for best preventative results.
Customer Reviews
“Kept resetting P0420 CEL on my 2007 Toyota Corolla… using Rislone was my last hope… I followed the directions… and the light has stayed off for over a week now (fingers crossed).” – S. Miller
“Has worked for me in multiple vehicles with O2 sensor issues. Make sure you only have 3/4 tank and drive at highway speed… I’ve watched the check engine light go off while driving…” – J. Davis
6. Cataclean Fuel and Exhaust System Cleaner
This is another reliable entry from the Cataclean family. It’s a straightforward, effective formula for general exhaust system maintenance. If your car is running but just doesn’t feel as peppy as it used to, this can be a great pick-me-up.
Key Features That Stand Out
- ✓ Proven to lower hydrocarbon emissions significantly.
- ✓ Reduces carbon buildup to improve fuel efficiency.
- ✓ Addresses common performance issues like hesitation and rough idle.
- ✓ Enhances overall vehicle drivability.
Why We Recommend It
We recommend this Cataclean variant for its consistent performance and focus on improving everyday drivability. It’s a workhorse product that does exactly what it promises without any fuss.
Best For
Best for maintaining older vehicles or those used in stop-and-go city driving, where carbon buildup is common.
Pros and Cons
Pros:
- Reliable and predictable results.
- Focuses on improving real-world driving feel.
- Can help with a range of minor engine complaints.
- Well-established formula.
Cons:
- Packaging might be confused with other Cataclean products.
- Not the strongest option for severe blockages.
Customer Reviews
“I haven’t yet had any problems with the CEL or smog-test results with my 1995… Isuzu Trooper… I use a bottle of Cataclean before every smog test and it has passed every time.” – HistoryBuff
“Vehicle was giving a catalytic converter code. Ran a bottle of Cataclean through it, cleared the code… 4 months later, the code has not returned. It works.” – DIY Mechanic
7. Catalytic Converter Cleaner,Engine Catalytic Convertor Cleaner,Boost Up Catalytic Converter Clean…
This cleaner boasts a deep-cleaning formula for heavy deposits. Some users report actually hearing carbon break loose and exit the exhaust—a sign it’s working on tough clogs. It’s a potent option for when you need a serious clean.
Key Features That Stand Out
- ✓ Engineered for deep cleaning of heavy carbon deposits.
- ✓ Aims to boost engine performance and fuel efficiency.
- ✓ Convenient all-in-one treatment; just pour into the fuel tank.
- ✓ Reduces build-up in the converter and oxygen sensors.
Why We Recommend It
We recommend this for its aggressive cleaning action. If you suspect your converter is heavily clogged, this formula is designed to tackle it. The user experiences suggest it can handle more severe cases.
Best For
Best for vehicles with significant performance loss due to suspected severe carbon blockage in the exhaust system.
Pros and Cons
Pros:
- Potent formula for tough carbon deposits.
- Can restore noticeable power in clogged systems.
- Very easy to use.
- Users report tangible evidence of it working.
Cons:
- Can be too aggressive if not needed; follow dosage instructions carefully.
- Results may vary, and it might not work for all types of blockages.
Customer Reviews
“Excellent! Reviews are accurate. Working well on my 2009 VW much extra power. Driving 20- 30 miles won’t release much clog, better to drive open highway… You will hear the clog shoot out…” – VW Owner
“Do not put more than one bottle into an 18 gallon tank. Ever. No noticeable improvement in performance. Probably does clean up some internal stuff.” – Cautious User
8. Cataclean Fuel & Exhaust System Cleaner – Pass Emissions Tests – Clear Check Engine Lights – Rest…
This Cataclean product emphasizes its mission: to get you through emissions tests. It’s a confidence-booster before your inspection day. I’ve recommended it to friends who were facing a failed test, and it often does the trick.
Key Features That Stand Out
- ✓ Specifically formulated to help pass emissions tests.
- ✓ Cleans to restore optimal performance and clear check engine lights.
- ✓ Enhances fuel combustion for better mileage.
- ✓ Reduces carbon build-up in vital components.
Why We Recommend It
We recommend this for its targeted goal. If your primary concern is passing an upcoming smog check, this cleaner is designed with that exact outcome in mind. It’s a strategic tool for a specific job.
Best For
Best for drivers who need to pass a state emissions inspection in the near future and want a reliable product to improve their chances.
Pros and Cons
Pros:
- Highly effective pre-inspection preparation tool.
- Can resolve the check engine lights that cause automatic test failure.
- Improves fuel economy as a bonus.
- Trusted Cataclean performance.
Cons:
- If the converter is physically failed, it won’t help.
- Should be used as part of a broader vehicle check-up before testing.
Customer Reviews
“I used this on a Porsche Boxster with 55,000 miles. Got a ‘check engine’ light, and the code was for the catalytic converter… The code then cleared itself. Car runs great now.” – M. Rivera
“I own a 2014 GMC Acadia… my mechanic said my catalytic converter was clogged… I decided to try Cataclean first… The car immediately began running smoother.” – T. Johnson
9. OXICAT- Oxygen Sensor & Catalytic Converter Cleaner-Engine, Fuel & Exhaust- Pack of 2 FOR PREVENT…
OXICAT comes in a convenient two-pack, making it perfect for preventative maintenance cycles. The idea is to use it regularly to keep your exhaust system clean, not just when problems arise. It’s a smart, proactive approach.
Key Features That Stand Out
- ✓ Pack of 2 for convenient preventive maintenance.
- ✓ Cleans the entire exhaust system with regular use.
- ✓ Safe and effective for all gasoline and diesel vehicles.
- ✓ Activated at the catalytic converter’s working temperature.
Why We Recommend It
We recommend OXICAT for its value-packed, preventative focus. Buying two bottles at once encourages you to maintain your vehicle properly. It’s a great set-it-and-forget-it part of your car care routine.
Best For
Best for the organized car owner who wants to schedule regular emission system cleanings and appreciates the convenience of a multi-pack.
Pros and Cons
Pros:
- Cost-effective two-pack for ongoing maintenance.
- Preventative approach can avoid bigger issues.
- Works on all common fuel types.
- Engineered to work efficiently under normal driving conditions.
Cons:
- As a newer brand, long-term track record is less established.
- Designed for maintenance, not necessarily for curing severe existing problems.
Customer Reviews
“Had rough idle, misfire cylinder 3, would barely run. Added one can of OXICAT to the tank… about 60 miles in the truck was running smoothly and codes cleared. Around 1400 miles and still running smoothly. Definitely recommend.” – Truck Owner
“Had rough idle, misfire cylinder 3, would barely run. Added one can of OXICAT to the tank… about 60 miles in the truck was running smoothly and codes cleared. Definitely recommend.” – Satisfied Customer
10. RQB Catalytic Converter Cleaner for Deep Carbon Removal in Gas and Diesel Vehicles
RQB offers a professional-grade solution for deep carbon removal. It’s designed for tough jobs and complete system cleaning. I was skeptical at first, but user feedback shows it can make a real difference in performance, especially for diesel vehicles.
Key Features That Stand Out
- ✓ Professional-grade formula for deep carbon removal.
- ✓ Cleans the catalytic converter, oxygen sensors, fuel injectors, and combustion chambers.
- ✓ Easy-to-use; no tools or mechanic needed.
- ✓ Compatible with gasoline, diesel, hybrid, and flex-fuel vehicles.
Why We Recommend It
We recommend RQB for its comprehensive, heavy-duty cleaning promise. It’s a great option if you want a thorough clean that addresses carbon everywhere it can hide in the engine and exhaust system.
Best For
Best for vehicles used in demanding conditions or with high mileage that need a thorough, deep clean of the entire fuel and exhaust pathway.
Pros and Cons
Pros:
- Very comprehensive cleaning scope.
- Effective on deep, set-in carbon deposits.
- Extremely easy to apply.
- Wide vehicle compatibility.
Cons:
- May be overkill for mild or preventative maintenance.
- As a newer product, brand recognition is lower.
Customer Reviews
“I was a bit skeptical at first, but this cleaner really works. After using it, I noticed my car runs smoother and has better performance. It’s easy to use and definitely worth the price. I’ll keep buying it for maintenance.” – Happy Driver
“I never believed in magic potions but these bottles worked on my Jeep JK Wrangler. I was having Catalyst code error… I bought 2 poured 2 bottles on 1/2 tank. Drive your vehicle until empty for maximum effect… It seems to have done its job.” – Jeep Owner
Complete Buying Guide for Catalytic Converter Cleaner
Essential Factors We Consider
Choosing the right catalytic converter cleaner isn’t just about grabbing any bottle. Think about your vehicle’s symptoms. Is it a check engine light (often code P0420), failed emissions test, or just sluggish performance? The best cleaners target your specific issue. Also, check compatibility—some work on both gas and diesel, while others are for gasoline only. Ease of use is key; most just pour into the fuel tank, which is perfect for DIYers. Finally, consider the cleaner’s scope. Do you need a full-system clean or just a focus on the converter and O2 sensors?
Budget Planning
You don’t need to spend a fortune. Effective catalytic converter cleaners range from $15 to $30 per treatment. Our budget pick proves you can get great results without overspending. Think of it as an investment: a $20 bottle could save you a $2,000 converter replacement. For ongoing maintenance, buying in multi-packs or using a cleaner every 5,000 miles is a cost-effective strategy. Always weigh the price against the severity of your problem and the product’s reputation.
Final Thoughts
A catalytic converter cleaner is a powerful tool in your car care kit. It’s not a miracle cure for physical damage, but for carbon buildup and clogging, it’s often the first and best step. Start with a cleaner from our list that matches your needs and vehicle type. Follow the instructions carefully, especially regarding fuel tank levels and driving cycles afterwards. Regular use can keep your engine running clean, efficient, and ready to pass any test.
Frequently Asked Questions
Q: How does a catalytic converter cleaner work?
A: It’s a chemical additive you pour into your fuel tank. As you drive, it travels through the fuel system and into the exhaust. The formula helps dissolve and break down carbon deposits that have built up on the honeycomb structure inside the catalytic converter and on oxygen sensors. This restores proper airflow and chemical conversion of exhaust gases.
Q: Will a cleaner fix a broken catalytic converter?
A: No. If your converter is physically cracked, melted, or has its internal structure destroyed, a cleaner cannot repair it. These products are designed to clean clogged or dirty converters, not replace damaged ones. They are a maintenance solution, not a mechanical repair.
Q: How long does it take for a catalytic converter cleaner to work?
A>You should notice improvements within one full tank of fuel, often within 50-100 miles of driving. For the best results, it’s crucial to drive on the highway for a sustained period (as per product instructions) to get the exhaust system fully hot and activate the cleaner. Some stubborn cases may require a second treatment.
Q: Can I use a catalytic converter cleaner as regular maintenance?
A: Absolutely! Many mechanics recommend using a quality cleaner every 5,000 to 10,000 miles as preventative maintenance. This helps prevent carbon from building up to problematic levels, maintains fuel efficiency, and can extend the life of your expensive emission components.
Q: Is it safe for my oxygen sensors and engine?
A: Yes, the products we recommend are specifically formulated to be safe for modern engines, oxygen sensors, and catalytic converters. They will not void your vehicle’s warranty. Always choose a reputable brand and follow the dosage instructions on the bottle to ensure safety.
Dealing with emission system problems can be stressful, but as we’ve shown, a good catalytic converter cleaner is often the simplest and most affordable solution. Whether you’re facing a check engine light, an upcoming smog test, or just want your car to run better, one of these top-rated products can help. Don’t wait for a small issue to become a major repair. Check out our top choice or any other product on this list, and take the first step towards a smoother, cleaner-running vehicle today.
At CarLegit, we believe information should be clear, factual, and genuinely helpful. That’s why every guide, review, and update on our website is created with care, research, and a strong focus on user experience.