How to clean a catalytic converter - step by step, easy to follow (2023)

How to clean a catalytic converter - step by step, easy to follow (1)

Reducing air pollution is something we should all take seriously.

As a car owner, you must do your part. This includes proper maintenance of the components that control pollutants.

In that regard, you are about to learn how to clean a catalytic converter.

In this article, we advise how to do it, both with and without uninstalling it.

We also explain why it's useful to clean it and what you need to know before you start. That includes which methods are not advisable and why.

If you're not sure if you want to do it yourself, that's fine. Find out below where to go and what you can expect to pay to have it handled by a professional.

What is a catalytic converter and why do you need to clean it?

Emission and fuel standards set by theEnvironmental Protection Agency(EPA) are strict, and rightly so. Transport in general is a major source of pollution in today's world.

The catalytic converter works to reduce toxic fumes emitted from your vehicle. The isolated chamber contains either pellets or a structure similar to a honeycomb. These are covered with a so-called catalyst.

Catalysts are any substances that can enhance a chemical reaction while remaining intact. In this process, they are usually noble orprecious metals such as platinum.

Harmful compounds in your exhaust, such ascarbon monoxide and hydrocarbons are oxidized. They emerge as carbon dioxide and water vapor, respectively. Harmful nitrogen oxides are eventually reduced to oxygen and nitrogen.

So the net result is that harmful gases and substances are converted into much less harmful substances as they pass through the catalytic converter.

Why should you clean it occasionally?

In case of uncleanness, the following can happen:

  • Ineffective gas control.
  • Unconverted tailpipe emissions may violate the law.
  • A decrease in engine performance.
  • Damage to other car functions.

Reduction of gas control

A clogged catalytic converter is not effective in controlling toxic gases. Your car will emit higher levels of emissions, possibly more than the legal level.


Smoking exhaust pipescan be a serious offense in some states and without a working catalytic converter you will not pass the emissions test.In Texas you can be fined up to $350.

(Video) How to clean catalytic converter while on car, customers request to spray down with cleaner

Performance drop

Auto parts are designed to rely on others and work in sync. Engine performance and fuel consumption decrease if the inverter is not taken care of.

Damage due to overheating

Overheating is another possible symptom that can cause damage to other vital mechanisms.

How do you know if the catalytic converter needs to be cleaned?

The symptoms associated with a faulty or dirty device can indicate many problems. It's a good idea to be on the safe sideconsult your on-board diagnostics system (OBD-II).

Once efficiency falls below 50 percent,your check engine light comes on. Use an OBD-II scanner to find out if the catalytic converter could be faulty.

Cleaning methods to avoid

There is a lot of information online about almost everything. That doesn't mean all of them are accurate or even safe to try. For the sake of your vehicle and your own, avoid these supposedly effective ways to clean the catalytic converter:

  • Paint varnish or thinner in your gas tank.
  • Immerse the device in strong chemicals.
  • Sawing off a welded whole.

Paint varnish or thinner in your gas tank

You may have seen guides to running lacquer or paint thinner through your gas tank to unclog a catalytic converter. Many solvents are used in the automotive industry, but not in this way. It is not wise to use non-automotive products on your vehicle.

The idea behind this trick is that the solvents in the paint or thinner break down the buildup blocking the converter.

However, such products are not made to circulate in a fuel system. They will cause more trouble than they're worth by causing internal damage. Solutions for your catalytic converter or emissions system are a much safer and more effective choice.

Unit of week in strong chemicals

A harsh cleaning agent, such as a grouting gel or bleach, may be powerful enough to remove the deposits on the device. If you soak it, the chances are even higher.

Despite their effectiveness, certain chemicals can be corrosive or acidic. They can disrupt the catalytic converter or even eat through the outside.

Sawing off a welded unit

The catalytic converter is bolted or welded on. If you know what you're doing and have the tools to hand, bolts can be loosened. But sawing off the unit is another story. The risk of accidents, both for you and your vehicle, is not worth the effort.

Don't forget that it also needs to be welded back on afterwards. The best approach is to go to a mechanic and have it done for you.

Cleaning a catalytic converter without removing it: using a cleaner

This is the easiest way to clear deposits and get your emissions back to normal. A bonus is that these cleaners can also work on your fuel system and oxygen sensors.

(Video) How To Clean A Catalytic Converter (Andy’s Garage: Episode - 149)

Required equipment

  • catalyst cleaner.
  • Fuel (either gas station access or fuel can).

Step by step process

  1. Make sure the product is compatible.
  2. Buy enough for treatment.
  3. Apply to your tank as directed.
  4. Drive around if you need to.

Step 1: Make sure the product is compatible

Some of these detergents are only compatible with dieselofgasoline, not both. Read the label before purchasing to make sure it is suitable for your vehicle.

Step 2: Buy enough for treatment

Larger cars require higher doses of your chosen product. Check if the quantity you buy is enough for your car.

Step 3: Apply to tank as directed

Pour the specified amount of product directly into your petrol tank. You may need to have an almost empty tank, depending on the brand of cleaner.

Step 4: Drive as needed

Start your engine and go for a ride to circulate the detergent. Check out the guidelines to know how far or how long you should drive.

If it works, there will be a noticeable improvement. Symptoms such as engine misfires, smoky exhaust and slow acceleration should have improved.

Cleaning a catalytic converter by removing and soaking it

We recommend that only intermediate to advanced home mechanics attempt removal. If a cleaner didn't work, the device may be seriously clogged.

If this tactic isn't effective either, you'll have to pay for a replacement. Driving without these pollution control components is irresponsible and illegal in many states.

Required equipment

  • Gloves.
  • Safety glasses.
  • Large container or tub.
  • Degreaser for cars.
  • Penetrating oil (e.g. WD-40).
  • Jack and jack stands.
  • Wrench (check bolt size in vehicle owner's manual or online).
  • Oxygen sensor wrench.
  • Buy towels.
  • Pressure washer.

Step by step process

Here's an overview of what you'll be doing:

  1. Let the vehicle cool down.
  2. Jack up your car. (We have manuals for thathow to use a bottle jack, Afloor jackand ascissor jack.)
  3. Wear your goggles and gloves.
  4. Find the inverter.
  5. Examine the fit.
  6. Remove the oxygen sensor(s).
  7. Treat the bolts with penetrating oil.
  8. Loosen the bolts, backwards.
  9. Remove the bolts while supporting the inverter.
  10. Inspect the device.
  11. Wipe it off.
  12. High-pressure cleaning, only with low pressure.
  13. Prepare the solution.
  14. Let it soak.
  15. Rinse and dry.
  16. Reinstall everything.
  17. Take a ride.

Step 1: Let the vehicle cool down

The exhaust pipe and related components get hot: The inverter alone can go up to 750 degrees Fahrenheit based on speed and driving conditions. Get your supplies ready while your car cools down completely.

Step 2: Jack up your car

Jack up your car so that you can comfortably stand under the exhaust. Use yourjack standsto keep it safe.

Step 3: Wear safety goggles and gloves

Protect your eyes from falling dirt and your hands from getting dirty.

Step 4: Find the converter

The device is located somewhere in the middle or at the end of your exhaust pipes. It will be in the form of a rounded or square device - hard to miss.

Step 5: Examine the fit

Is the unit welded or bolted? Remember that welding is best done by a professional mechanic.

(Video) How to Clean Your Car's Catalytic Converter using Lacquer Thinner

Step 6: Remove the oxygen sensor

Carefully remove the sensor (or sensors) using your oxygen sensor wrench and set it aside.

Step 7: Treat bolts with penetrating oil

Generously apply penetrating oil to all bolts. They are probably firmly attached or partially corroded. Let the oil loosen them for a few minutes.

Step 8: Loosen the bolts, back to front

Start with the bolt closest to the end of your exhaust. Work from there. Do not remove them yet.

Step 9: Remove the bolts while supporting the converter

Hold the device so that it does not fall on the floor. Remove each bolt and set them aside so you don't lose them.

Step 10: Inspect the unit

Is it melted or do you hear rattling when you shake it? These are indicators that the part is ready and should be discarded.

You have no choice here but to get a replacement. Until it is replaced, your car should not go anywhere but to your mechanic.

If everything seems to be OK, continue to the next step.

Step 11: Wipe

Wipe the device with a kitchen towel to remove any surface residue.

Step 12: Pressure Washer: Low Pressure Only!

Set your pressure washer on low. Hose down both the inlet and exhaust pipe to remove deposits and nasty contaminants.

Step 13: Prepare the solution

Fill your container with hot water and add the degreaser to the water.

Step 14: Let it soak

Place the device in your pre-prepared solution. Let it soak for 30 minutes to an hour - you don't want to overdo it.

Step 15: Rinse and Dry

Rinse it with your pressure washer and keep it on low pressure. Place the device on a kitchen towel and allow it to dry completely. The safest bet is to leave it for at least a few hours, but the longer you can wait, the better.

Step 16: Reinstall everything

Once it's completely dry, collect your bolts. Reattach the part and your oxygen sensor (or sensors) as well.

(Video) Catalytic converter cleaning in less than 5 Minutes/Cleaning Catalytic converter with AUTOOL Kit

Step 17: Go for a ride

Drive around for a while to see if there is a difference. If nothing or little has changed, replacement is in order.

Going to a professional to clean the catalytic converter: what to expect

You can visit a mechanic or a carbon cleaning center to get quotes and see what your options are:

Carbon cleaning center

These are centers that specialize in removing carbon deposits from car engines. You can take your vehicle there, they will do an inspection and then provide a quote.

They use hydrogen to decarbonise the inverter, instead of cleaning it as we described. This is not something you should try at home.

Your mechanic

Most mechanics will recommend that you use a catalytic converter cleaner or replace it. It is unlikely that they will offer to remove and clean the device.

If all cleaning methods have failed, get ready for some bad news. Replacements are far from cheap - you can expect to pay a minimum of $1,000.

Labor costs are lower than what you pay for the part itself. This is due to the precious metals in it that serve as a catalyst.

How often should you clean your catalytic converter?

Using a suitable product from time to time is cheaper than buying a new device. Aim to do this three to four times a year for heavily used vehicles.

Those of you who don't drive very often can get by with one treatment a year. All you have to do is pour the solution into your gas tank and drive around. Or have it done professionally at a carbon cleaning center. That's much easier than removing the device or paying hundreds of dollars for a new one.


We've shared how to clean catalytic converters, with and without removal. Still, uninstalling the device should be a last resort, not the first thing you try.

Cleaning solutions are effective and easier to use. They can extend the life of the converter by keeping it from clogging.

Now that you know how costly replacements can be, make it a priority to take care of your inverter and your vehicle in general. You want to put off buying a new one as long as possible.

We hope you found this article helpful. Do you have questions for us? Leave a comment below so we can get back to you!

(Video) Effective way to clean Catalytic Converter Part 1.This works 95% of the time.


Can I clean my catalytic converter myself? ›

The best method is using water and lacquer thinner. However, there is no proven step or process for cleaning the catalytic converter this way, so you might want to search online for a few additive cleaners, such as Oxicat or Cataclean, that help remove carbon deposits slowly before attempting.

How do you unclog a catalytic converter cheaply? ›

What can you do? Drive the car at high speeds for a few miles. Try to get to 2500-3000 RPMs. This way, the exhaust system heat will burn off the catalytic converter deposits and unclog the converter.

What works to clean catalytic converter? ›

Top Catalytic Converter Cleaners
  • CataClean Fuel Cleaner 16.7oz. ...
  • Rislone Cat Complete Fuel, Exhaust and Emissions System Cleaner 16.9oz. ...
  • CRC Guaranteed To Pass Fuel System Cleaner 12oz. ...
  • Chevron Techron Fuel System Cleaner 12oz. ...
  • Gumout Regane Complete Fuel System Cleaner 12oz. ...
  • STP Ultra 5-IN-1 Fuel System Cleaner 12oz.

Can you unclog a catalytic converter without replacing it? ›

You can fix a catalytic converter without replacing it if the damage is minor. Some techniques to try include using fuel additives, removing the catalytic converter and cleaning it, and driving your car hard to help it reach a high operating temperature.

How long does it take catalytic converter cleaner to work? ›

Dump all the bottle's contents into your fuel tank. This is the same place where you would put gas. Step 2: Drive your vehicle for at least 15 minutes to allow the Cataclean to get into your vehicle's parts. Step 3: If you have error codes on your on-board computer (OBDII), clear them after you've driven the vehicle.

How do I know if my catalytic converter is clogged? ›

If you're noticing slow powertrain performance, reduced acceleration, a smell of rotten eggs or sulfur from the exhaust, dark exhaust smoke, or extreme heat from under the vehicle, these are symptoms of a clogged Catalytic Converter, and it should be replaced quickly.

Will seafoam clean catalytic converter? ›

Sea Foam does not clean catalytic converters [SOLVED] | Sea Foam.

Can I clean my catalytic converter with soap and water? ›

Dish soap and water should be added to a large bucket. Soak the catalytic converter, which is now dismantled, in the bucket overnight. Make sure that the converter's honeycomb is free of debris. If so, replace the catalytic converter and reassemble the exhaust system.

How long can a clogged catalytic converter last? ›

Over plenty of years, the Catalytic Converter can deteriorate since it's clogged, contaminated, or physically damaged. So it's best to wait the 10 years, or if you have any concerns that you have a clogged catalytic converter, then you need to have it personally inspected prior to thinking about getting it replaced.

What happens if your catalytic converter is completely clogged? ›

When a catalytic converter is clogged, it causes a large amount of smoke to surge through the exhaust system. This may lead to frequent stalling or make the car difficult to start at all. If the CAT system has a major blockage, your engine will likely sputter and only start a few seconds later.

Is there an additive to clean catalytic converters? ›

Mr. Gasket Cataclean is a fuel and exhaust system cleaner that reduces carbon build-up and cleans your vehicle's catalytic converter, oxygen sensors, fuel injectors, and cylinder heads. Cataclean does not alter fuel composition and is safe for gasoline, diesel and hybrid engines.

Can bleach clean catalytic converter? ›

To avoid damaging your catalytic converter during cleaning, avoid the following: Soaking the component in grout-eating gel, bleach, or similar corrosive chemicals that can damage the catalyst. Pouring paint lacquer or thinner in your gas tank.

Is it OK to drive with a clogged catalytic converter? ›

You shouldn't drive your car if a catalytic converter is completely clogged. If you do, you can expect the restricted exhaust flow to hinder your engine performance, which leads to your engine idling for a few minutes and then dying.

What are the 3 most leading failures of a catalytic converter? ›

Most catalytic converter failures fall under one of three categories: Overheated, melted or broken converters.

How does a car run with a clogged catalytic converter? ›

A clogged catalytic converter keeps exhaust gases in your car, causing the engine to stall from increased exhaust pressure. If your car seems fine at first, but then starts sputtering or stalling, it could be a sign of a catalytic converter issue.

Can you put catalytic converter cleaner in a full tank of gas? ›

Yes, a whole bottle of Cataclean is recommended for 15 litres of fuel, roughly a quarter of a tank. So if you have half a tank left in your car, you can use two bottles. If you run your car down to half a tank and use Cataclean but it seems to have no effect, refill your tank fully.

How do I know if my catalytic converter needs cleaning? ›

A catalytic converter is a part of a car's engine that removes poisonous carbon from the engine's emissions. When the converter is clogged or dirty, the check engine light in your car will turn on to let you know that something is wrong.

Does Cataclean clean o2 sensors? ›

Cataclean is a patented fuel and exhaust system cleaner that reduces carbon build-up and also cleans your vehicle s oxygen sensors, fuel injectors and cylinder heads.

What does a blocked catalytic converter sound like? ›

What does a bad catalytic converter sound like? Often, a clogged catalytic converter sounds like a rattling noise is coming from under your vehicle and engine when you're starting, idling or driving. Excess heat or damage in the converter can break apart the honeycomb materials, resulting in the rattling noise.

Can I put Sea Foam in a full gas tank? ›

Treatment Recommendations

Small engines: add whenever you refuel. For engine equipment used regularly, add Sea Foam to a fresh tank fill every 3 months or sooner. For all other engines and fuel tanks (not used regularly): Add Sea Foam to every tank of fuel.

Does Sea Foam clean O2 sensors? ›

SEA FOAM MOTOR TREATMENT can help keep your fuel system clean, minimizing the dirty, unburned carbon that can build up on O2 sensors, causing them to fail.

Is Cataclean good for your engine? ›

Cataclean is safe for both petrol and diesel engines, you don't have to buy different versions for each fuel type. One bottle does both.

What is the best fuel additive to clean O2 sensors? ›

Can I Just Clean My O2 Sensor? The short answer is that our strongest gasoline fuel additive, B-12 Chemtool Total Fuel System Clean-Up (part #2616), and a good tune-up might indirectly solve your problems.

Can I pressure wash my catalytic converter? ›

You can unclog your car's catalytic converter with a catalytic converter cleaner or by removing the part to pressure wash and degrease it before reinstalling it.

Will water ruin catalytic converter? ›

Even water getting in the tailpipe can cause serious damage. The catalytic converter can be ruined -- a $1,000 repair -- and it may not be noticed until failing an emissions test.

What will happen to my car if I don t fix the catalytic converter immediately? ›

If a catalytic converter develops any issues, it may have an effect on the vehicle's engine since it's installed within the car's exhaust system. If the converter gets blocked or clogged, it will restrict the exhaust flow, which will cause a reduction in the car's acceleration, power, and fuel economy.

Can a clogged catalytic converter damage engine? ›

Usually, a clogged catalytic converter will overheat and can have damaging impacts on your car's engine. Anytime you experience an engine misfire, contact a reliable mechanic right away for catalytic converter repair or replacement services.

How do you unclog an exhaust? ›

Using a cloth, clean the exhaust tip, then for inside the exhaust, use a hard bristled brush, cleaning as deep in the tail pipe as you are able to. Applying a degreaser will help in breaking up carbon deposits and rust. Using a dry cloth, apply a degreaser to the inside and outside of the exhaust.

Does catalytic converter cleaner really work? ›

The short answer is no. Using one of these products likely results in ameliorated symptoms, mainly because they contain additives that will clean carbon deposits from your engine's fuel and exhaust systems. Mind you, they won't completely eliminate them or magically repair your damaged catalytic converter.

How many bottles of Cataclean do I need? ›

Depending on how clogged your engine is, use 1 - 5 consecutive bottles of Cataclean in the gas tank and drive at highway speeds as much as possible. Once back… see more. Depending on how clogged your engine is, use 1 - 5 consecutive bottles of Cataclean in the gas tank and drive at highway speeds as much as possible.

Can gas treatment clean catalytic converter? ›

This fuel additive can help to “scrub” the inside of your catalytic converter, removing the deposits that are preventing it from working correctly. Used as directed, it can also help clean your oxygen sensors, making sure that they're reading correctly as well as extend the time between needed tune-ups.

Can you use throttle body cleaner on catalytic converter? ›

Effective – quickly removes gum, varnish, sludge, carbon, and other deposits. Easy to use – convenient aerosol with 360° spray-anyway valve. Safe to use – contains no fluorocarbons or chlorinated solvents; will not harm gaskets, oxygen sensors, and catalytic converter.

Can you use oven cleaner to clean a catalytic converter? ›

Run water and oven cleaner through the cat. Spray the oven cleaner in the cat and let it sit for a few minutes. Then run water through the car while blowing air in at the same time. Rinse, then install and drive the car until the cat is hot.


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