Best Additive For Catalytic Converter: Compare 10 Options

#1 · Best Overall

1. Cataclean Fuel & Exhaust Cleaner

• Size: 16 Fl Oz (Pack of 2)

Best for: Two-bottle emissions preparation.

Why it ranks #1: Its gasoline formula explicitly targets catalytic converters, injectors, and oxygen sensors, and it comes as two 16-ounce bottles.

Cataclean’s stated cleaning reach includes catalytic converters, injectors, and oxygen sensors, making its two 16 oz bottles relevant to owners addressing several emissions-system components. The gasoline-engine formula is also presented for emissions preparation, while its fuel-injector and cylinder-head cleaning claims connect that task with combustion and mileage support.

Cataclean targets carbon buildup across the converter, injectors, and oxygen sensors, so its scope reaches beyond a single exhaust component. The listing also says it cleans fuel injectors and cylinder heads, connecting treatment with fuel combustion, performance, and mileage. Two 16 oz bottles provide a two-treatment supply. Its stated application is gasoline engines, and the emissions-related claims make it a consideration before inspection, though the listing does not describe it as a repair for damaged hardware.

Skip it if you need a cleaner expressly compatible with diesel vehicles; Cataclean’s supplied application is gasoline engines.

Consider this two-bottle option for gasoline-engine owners who want cleaning claims spanning converter, injectors, and oxygen sensors before emissions checks. Its listed application is gasoline, and it should not be treated as a fix for damaged components.

Listed on Amazon as: Cataclean Fuel & Exhaust System Cleaner for Gasoline Engines, 16 oz, 2 Pack

#2 · Best Specified Single-Bottle Formula

2. Liqui Moly Catalytic System Clean

• Size: 10.14 Fl Oz (Pack of 1)

Best for: Gasoline catalytic-system maintenance.

Why it ranks #2: The 300 ml liquid is listed for all gasoline engines with a catalytic converter and targets both injection and combustion systems.

Liqui Moly’s 300 ml treatment cleans both the injection system and combustion chamber, linking fuel-side cleaning with catalytic-converter care in one additive. It suits gasoline engines equipped with a catalytic converter, and its stated soot-protection purpose makes it a focused option for routine system maintenance rather than a mechanical repair.

The formula cleans the injection system and combustion chamber, which supports improved fuel combustion instead of focusing only on the converter. Liqui Moly also says it helps protect the catalytic converter from soot clogging and prevents corrosion in the fuel system. Its 300 ml liquid format is a single-bottle treatment, and the product is suitable for gasoline engines with a catalytic converter. The description also identifies it as tested for use with turbochargers and catalytic converters.

Skip it if you need a cleaner explicitly listed for diesel or hybrid vehicles; this formula is specified for gasoline engines.

Choose this for gasoline-engine maintenance when you want injection-system and combustion-chamber cleaning alongside soot protection. Its stated fit is limited to gasoline engines with catalytic converters, so it is not the match for a diesel-focused application.

Listed on Amazon as: Liqui Moly Catalytic System Clean 300 ml 7110. Cleans The Injection System and The Combustion Chamber.

#3 · Best OBD-Code Support

3. Rislone Cat Complete

• Weight: 1.08 lb

Best for: OBD-code and odor focus.

Why it ranks #3: Its listing names fuel, exhaust, and emissions cleaning and says it can address P0420 and other OBD codes.

Rislone Cat Complete specifically lists support for clearing P0420 and other OBD codes, giving code-focused buyers a clear reason to consider it. Its feature set also names fuel, exhaust, and emissions-system cleaning plus sulfur-odor deodorizing, bringing diagnostic and exhaust concerns into one treatment’s stated scope.

The listed detergents and heavy-duty cleaning solvents target contaminants, soot, carbon buildup, and oily residue in components including fuel injectors and combustion chambers. That broad cleaning scope may appeal when maintenance concerns span fuel and exhaust systems. Rislone also identifies P0420 and other OBD-code support and sulfur-odor deodorizing, offering distinct reasons to consider it around emissions troubleshooting. The product is a one-pack cleaner, and its listed 50-state legality and EPA registration are relevant to buyers checking emissions-related use.

Skip it if you need explicit gasoline, diesel, or hybrid compatibility; Rislone’s supplied specifications do not name a fuel type.

This fits buyers prioritizing listed OBD-code support, sulfur-odor treatment, and fuel-and-exhaust cleaning in one product. Since the supplied details do not state fuel-type compatibility, check that limitation against your vehicle before selecting it.

Listed on Amazon as: Rislone 4720 Cat Complete Fuel, Exhaust, Emissions System Cleaner, 1-Pack

#4 · Best One-Step Application

4. EZ PASS Emissions Treatment

• Weight: 15.2 oz

Best for: One-step gasoline smog preparation.

Why it ranks #4: The gasoline treatment directs users to pour one bottle into a full tank and describes cleaning the converter, oxygen sensors, and injectors.

EZ PASS calls for pouring one bottle into a full tank, giving gasoline owners a clearly stated one-step routine during normal driving. The treatment targets the catalytic converter, oxygen sensors, combustion chamber, and injectors, with emissions-system support positioned for preparation before scheduled smog or state inspections.

The full-tank instruction creates a straightforward workflow: pour one bottle into the tank and let treatment occur during normal driving. EZ PASS lists cleaning support for the converter, oxygen sensors, combustion chamber, and injectors, connecting inspection preparation with several fuel and emissions components. It also says the formula assists with certain emissions-related diagnostic codes. The listing presents emissions support rather than mechanical repair, and its inspection-focused positioning makes it most relevant to gasoline owners preparing for a scheduled check.

Skip it if you need explicit fuel-type compatibility before use; the supplied EZ PASS details do not name gasoline, diesel, or hybrid vehicles.

This is a practical choice for drivers who want a stated full-tank routine before an emissions inspection and cleaning support across several components. The supplied compatibility details do not name fuel types, so verify that boundary for your vehicle.

Listed on Amazon as: EZ PASSTM Emissions Treatment | Catalytic Converter & O2 Sensor Cleaner | Emissions System Support | Smog Test Prep | 16 Fl oz, 2-Pack

#5

5. Dura Lube Severe Catalytic Treatment

• Size: 16 Fl Oz (Pack of 1)
• Weight: 16 oz

Best for: Catalyst oil-poison protection.

Why it ranks #5: Its 16-ounce treatment is intended to protect the catalytic system from oil poisons and is recommended for use before converter replacement.

Dura Lube focuses on protecting the catalytic system from harmful oil, distinguishing it from cleaners centered primarily on soot or carbon deposits. The 16 fl oz treatment also claims to reduce phosphorus and zinc retention at the catalyst inlet, making it a candidate to consider before replacing a converter.

The product says it shields the catalytic system from harmful oil and helps maintain catalytic efficiency, a specific focus for buyers concerned about oil-related catalyst exposure. It also claims to reduce phosphorus and zinc retention at the catalyst inlet. The 16 fl oz liquid bottle is intended for engine use and can be added anytime, according to the listing. Dura Lube additionally claims fuel-economy help and lists universal fit across engines, but it does not promise to repair a failed converter.

Skip it if you want a product with explicit gasoline, diesel, or hybrid compatibility; Dura Lube lists universal fit but no fuel categories.

Choose this when oil-related catalyst protection and treatment before converter replacement are your priorities. Its universal-fit claim is broad, but the supplied details do not identify specific fuel types, so that distinction may matter for your vehicle.

Listed on Amazon as: Dura Lube Severe Catalytic and Exhaust Treatment Cleaner Fuel Additive, 16 fl. oz., (PN: HL-402409 PDQ3)

#6

6. MotorPower Care Catalytic Cleaner

• Size: 8.45 Fl Oz (Pack of 2)
• Weight: 0.61 kg

Best for: Gasoline and hybrid cleaning.

Why it ranks #6: The two-bottle cleaner lists gasoline and hybrid compatibility, but its own caution says it will not repair a cracked, broken, or melted converter.

MotorPower Care’s two-bottle package combines catalytic-converter cleaner with claims of gasoline and hybrid compatibility, giving owners of either vehicle type a listed cleaning option. Its clearest boundary is equally important: the product is for cleaning, not repairing a converter that is cracked, broken, or melted.

The listing describes the formula as compatible with gasoline and hybrid vehicles, making those the stated application types. Its two 8.45 fl oz bottles provide a paired supply, and an included funnel supports pouring during use. MotorPower Care says the cleaner can restore engine performance and support emission reduction when the converter is intact. That condition matters: cleaning is not a fix for a cracked, broken, or melted converter, so diagnosis should come before relying on an additive.

Skip it if you have a cracked, broken, or melted converter; this cleaner is expressly not a repair for that damage.

This package fits gasoline and hybrid owners seeking a cleaner for an intact converter, with a funnel included for pouring. It is not an alternative to repair or replacement when the converter is physically cracked, broken, or melted.

Listed on Amazon as: MotorPower Care Catalytic Converter Cleaner 2-Pack — Pass Smog & Emissions Test, Fix P0420/P0430 Check Engine Light | O2 Sensor & EGR Cleaner | Fuel Additive, 8.45 fl oz Each

#7

7. Ciirvoe Catalytic Converter Cleaner

• Weight: 1.39 lb

Best for: Multi-fuel pour-in treatment.

Why it ranks #7: Its description covers converter and fuel-system deposits and lists gasoline, diesel, hybrid, and flex-fuel compatibility, though details are limited.

Ciirvoe lists compatibility with gasoline, diesel, hybrid, and flex-fuel vehicles, giving this six-piece cleaner broad stated fuel-type coverage. Its easy pour-in application during refueling ties the treatment to an ordinary fueling stop, while the described targets include carbon deposits in the converter, injectors, and cylinder heads.

This treatment addresses carbon deposits in the catalytic converter, fuel injectors, and cylinder heads, connecting exhaust-system care with fuel-system cleaning. The description says it supports smoother operation and helps reduce roughness and hesitation by promoting cleaner combustion. Its pour-in use during refueling offers a straightforward workflow, while listed compatibility spans gasoline, diesel, hybrid, and flex-fuel vehicles. Each unit is 120 ml, and the supplied storage guidance is to keep it in a cool, dry place.

Skip it if you need a clearly stated per-tank dosage; the supplied Ciirvoe details give no treatment amount for each fill.

This suits drivers seeking a pour-in treatment with broad listed fuel compatibility and targets across converter and fuel-system components. Check that its unspecified per-tank dosage works for your preferred maintenance routine before choosing it.

Listed on Amazon as: 6Pcs Catalytic Converter Cleaner Kit,Boost Up Catalytic Convertor Cleaner,Exhaust System Pipe Carbon Removal Cleaner Treatment Additive Oil,Fuel System Treatment Oil Additive

#8

8. Timeno Catalytic Converter Cleaner

Best for: Multi-vehicle three-piece option.

Why it ranks #8: The listing names cars, trucks, hybrids, and diesel vehicles, but provides little detail about the formula or its application.

Timeno lists compatibility with cars, trucks, hybrids, and diesel vehicles, making its three-piece cleaner the broadest specifically named vehicle-type option in this group. The title frames it as a catalytic-converter and fuel-system treatment, while the supplied specifications identify bottles as the container type but give no treatment volume.

The compatibility field names cars, trucks, hybrids, and diesel vehicles, giving buyers specific vehicle categories to compare against their own. The title describes catalytic-converter cleaning, pipe-carbon removal, and fuel-system treatment, so the stated scope spans exhaust and fuel-system maintenance. Three pieces are identified in the product title, and the specifications list bottles as the container type. No bottle volume or dosage is supplied, which limits how precisely buyers can plan the treatment routine from the listing alone.

Skip it if you need a defined treatment dose or bottle volume; Timeno’s supplied specifications do not state either.

Consider this for car, truck, hybrid, or diesel owners looking for a multi-piece cleaner identified for converter and fuel-system treatment. The broad vehicle list is useful, but missing volume and dosage details constrain planning.

Listed on Amazon as: Timeno 3Pcs Catalytic Converter Cleaner, Boost Up Catalytic Convertor Cleaner, Pipe Carbon Removal Cleaner Treatment Additive Oil, Fuel System Treatment Oil Additive for Gas and Diesel Car

#9

9. Vizela Catalytic Converter Cleaner

• Size: 120 milliliters

Best for: Three-bottle 120 ml set.

Why it ranks #9: The three-piece, 120 ml listing names car, flex-fuel, hybrid, and truck compatibility, but supplies few cleaning or use details.

Vizela supplies three bottles of 120 ml each, a concrete package detail for buyers planning to keep multiple treatments on hand. Its compatibility listing names cars, flex-fuel vehicles, hybrids, and trucks, while the title describes catalytic-converter, exhaust-pipe carbon, and fuel-system treatment purposes.

The listed vehicle types cover cars, flex-fuel vehicles, hybrids, and trucks, giving buyers several stated categories to compare with their vehicle. Its title identifies catalytic-converter cleaning, exhaust-pipe carbon removal, and fuel-system treatment, indicating a broad maintenance purpose across related systems. The 120 ml size and three-piece kit make the quantity clear for storage and planning. However, the supplied details do not provide a per-tank dose or explain the application steps, limiting guidance for first-time users.

Skip it if you need a specific per-tank dose before buying; Vizela’s supplied details do not state one.

This suits owners of cars, trucks, hybrids, or flex-fuel vehicles seeking a three-bottle cleaner identified for converter and fuel-system treatment. The package quantity is clear, but dosage and application directions are not provided in the supplied details.

Listed on Amazon as: Catalytic Converter Cleaner Auto Parts Engine, Exhaust System Pipe Carbon Removal Cleaner Treatment Additive Oil, Fuel System Treatment Oil Additive for Gas and Diesel Car(120 ml) (3pcs)

#10

10. Generic Catalytic Converter Cleaner

• Weight: 13.7 oz

Best for: Three-piece gas and diesel set.

Why it ranks #10: It is described as an exhaust-system additive for gas and diesel cars, but the listing provides almost no formula, compatibility, or application specifics.

This Generic-branded listing identifies a three-piece catalytic-converter cleaner for gas and diesel cars, giving owners of those fuel types a multi-unit treatment option. The title also frames its purpose as exhaust-pipe carbon removal and fuel-system cleaning, although the supplied product details do not spell out a dosage or application procedure.

The title describes the product as an exhaust-system pipe carbon-removal treatment and fuel-system cleaner, connecting its stated purpose to both exhaust and fuel-system maintenance. It is identified for gas and diesel cars, giving those buyers the clearest compatibility guidance available in the listing. Three pieces are included according to the title. However, the supplied specifications provide no dosage, bottle volume, or step-by-step use details, so buyers who need a defined treatment schedule have limited guidance here.

Skip it if you need a stated bottle volume or treatment dosage; the supplied product information does not provide either.

This may suit gas- or diesel-car owners who want a three-piece product identified for exhaust-pipe and fuel-system cleaning. Its limited usage details make it a weaker fit when a precise dose or treatment schedule is essential.

Listed on Amazon as: 3Pcs Catalytic Converter Cleaner, Exhaust System Pipe Carbon Removal Treatment Additive, Fuel System Cleaner Oil Additive for Gas and Diesel Cars