How to Clean a Catalytic Converter (Without Removing it)

A catalytic converter is collecting a lot of particles and other stuff coming out from the engine. This means that it can get clogged and need a cleaning. Here’s how to do it

  • By Magnus Sellén
  • Updated: July 31, 2022

Are you struggling with the P0420 code and want to clean your catalytic converter, but realize that it’s a lot of work to remove the catalytic converter, and you want to do it without removing it?

Then this article is for you. We will discuss how to remove the catalytic converter without removing it from your car to get the best results, and you may save a lot of money by doing so.

If you want to learn more about the P0420 code before cleaning it, you can check our article about this here: P0420 code.

Things to consider before starting

There are some things that you have to consider before trying to clean your catalytic converter. In a lot of cases, the parts inside the catalytic converter will become loose. If this is the case, you can’t repair your catalytic converter without removing and replacing it.

1. Too clogged

If your catalytic converter is so clogged that the engine will not run, you have to remove the catalytic converter and either use special tools or replace the whole catalytic converter.

2. Check/listen for loose parts

You can take a rubber hammer and hit your catalytic converter carefully, and listen to ascertain if there seem to be any loose parts inside it. If you can hear loose parts, I recommend removing and inspecting the catalytic converter because the loose parts could come even looser and clog your exhaust pipe totally, which may cause your vehicle to stop while driving.

3. Purified catalyst

Remember that your catalytic converter may have been cleaned inside, and the parts inside it may have blown out from the exhaust pipe. This can be tough to see without removing it, and if you suspect this, remove the catalytic converter and check it.

4. Oil consumption

Your catalytic converter may have got clogged due to internal oil consumption, caused by oil entering the cylinders and getting combusted and burned inside the hot catalytic converter.

If this is the case, you should always repair the internal oil leak before using this cure, as it may only work for a short time until the catalytic converter is clogged again. Common symptoms of an internal oil leak are clogged crankcase ventilation, broken valve seals, or piston rings. Always check the crankcase ventilation first.

How to clean your catalytic converter without removing it

If you have checked and listened carefully for any loose parts inside your catalytic converter and your are sure that the car is not burning oil, follow these few steps to clean your catalytic converter:

Total Time: 10 minutes

Step 1. Get Oxicat Catalytic converter cleaner

The easiest way to clean a catalytic converter without removing it is by using a catalytic converter cleaner product. One product we recommend is the OXICAT – Oxygen Sensor & Catalytic Converter Cleaner .

You can find more of these products in our guide: Best Catalytic Converter Cleaners. You tap it into your fuel tank, and it does not matter if you have petrol, diesel, or hybrid car. This will help clean the catalytic converter; it will also clean your O2 sensors and the whole exhaust system.

Remember that this product will not repair mechanical faults inside your catalytic converter if it’s cracked, broken, or too clogged. This is a cleaner for a slightly clogged catalytic converter that lost its power due to time.
Of course, you can also use other brands of catalytic cleaners, but this one has worked best for me so far.

  • Safe and effective for all petrol.
  • Engineered to clean the entire exhaust.
  • OXICAT is activated when the catalytic.
  • Proven safe and effective by the Pros.

Step 2. Pour the Catalytic converter cleaner into the fuel tank.

Check the cleaner’s manual and pour in the exact amount of cleaner into the fuel mentioned in the manual. Ensure that you are using the required amount for your car type and engine, so you are not using too much of the product – this can cause even more damage to your catalytic converter in some cases.

Step 3. Take your car for a drive

Drive your car a couple of miles to see if your car runs better than before. You can also try to drive your car at high RPM’s over 3000 for a long distance to get the catalytic converter really hot to burn out the clog inside it.
Always keep an eye on the coolant temperature though to make sure that you are not overheating the car.

  • Safe and effective for all petrol.
  • Engineered to clean the entire exhaust.
  • OXICAT is activated when the catalytic.
  • Proven safe and effective by the Pros.

The Oxicat did not work for me, what to do now?

If you tried the Oxicat catalytic converter cleaner, but the problem still persists, there is not much more to do than removing the catalytic converter to inspect it and to make sure it looks okay. Remember that there can be other causes of the P0420 trouble code like faulty O2 sensors or exhaust leaks and the problem may not be in your catalytic converter.

Removing the catalytic converter is often quite easy on most cars if you can get the rusty bolts loose. In some cars, the catalytic converters are installed directly on the turbocharger, and in these cases, the removal of the catalytic converter may be more difficult.

If you still think that your catalytic converter is clogged and looks okay while inspecting it, you can try to clean it in a bath with water and lacquer thinner. This does sometimes work, and it may save you some money.

Check this link for Amazon’s version of lacquer thinner:

  • Package Dimensions: 14.5 L x 11.25 H x.
  • Package Weight: 36 pounds
  • Country of Origin : United States
  • Part Number: NA-LTR182

If you tried both the Oxicat cleaner and lacquer thinner, and you can not see any visual signs of damages, but the problem still insists – There is no option other than replacing the catalytic converter.

You should also check for other problems – it might not be the catalytic converter causing your problem.

Catalytic converters are often expensive, and this is because there are noble metals inside them that cost a lot to produce.

Frequently Asked Questions

Does premium gas clean a catalytic converter?

While premium gas likely won’t clean your catalytic converter, it can prevent it from becoming clogged in the first place. However, there are many reasons why a catalytic converter can become clogged, so it does not necessarily have to do with the fuel.

Can you drive with a clogged catalytic converter?

Driving with a clogged catalytic converter is not recommended, and it depends on how clogged it is. A clogged catalytic converter will make your car run poorly and will increase your emissions. If you suspect your catalytic converter is clogged, take your car to a mechanic for a checkup. Driving with a clogged catalytic converter can also cause severe damage to other parts of the engine.

What is the best way to clean a catalytic converter?

The best way to clean a catalytic converter is to remove it from the vehicle and use a special machine to clean it with a good cleaning fluid. However, these are very expensive and are for commercial use.

Is it better to clean or replace the catalytic converter?

Replacing the catalytic converter with a new one is definitely the best way to avoid problems in the future. However, catalytic converters can be very expensive and therefore may not be the best solution for you. Cleaning a catalytic converter is a much cheaper solution.

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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I have 07 mit. Eclipse 4cyl manual that had timing belt go out and had replace engine valves, afterwards now will make 3rd exhaust manifold gasket having to replace. Believe Cadillac converter may be causing this to happen. Was hoping for any alternative to resolve problem w/o replacing Cadillac converter. Any advice greatly appreciated.

I have 2007 Nissan pathfinder. Bad smell from exhaust and rattling sound.

I have a 2004 Ford Expedition and I just replaced the motor. The truck was running fine before the motor went out,now after the new motor is in the truck seems to lack power and I’m thinking that the catalytic converters are clogged due to seeing lil chunks that look like wood laying behind by the tail pipe. What can I do?

Hey bud..shake the tail pipe.and exhaust if you can..can hear a rattle..not good..those wood chips sound like the element inside your looks like a bee hive..kinda is falling apart:( need a new one

Hi. Can you still drive with a bad catalytic converter? I don’t want to put my kids in danger. Can I try oxicat if i don’t know if the cat.con. needs replacing?

I have an 09 Honda Accord and the check engine just came out with a p0420 how can I tell is catalytic converter or just a sensor


Hello, We have a 2009 Hyundai Santa Fe — live in south Florida — and it has been running rough on start up. It was taken to a repair shop yesterday and we were told the catalytic converter needs to be replaced. However, I found your information on Oxicat and we would like to try it. Is one use of it recommended, or is it something that should be added every time we fill our car with gas? Is the entire can used at one time?

O have a 04 ford Taurus and changed the fuel filter,egr vale,egr valve sensor but the plastic egr sensor and 2 little hoses keep melting. I took it to get it tested and thats all pops up on the test. I don’t know why it keeps melting them things

Yes, you can use a can of detergent in half a fuel tank and then speed up the car until the cleaning is done properly

Stephen V. Viccari

Yes, it should be the same cat on both trucks.

Hi, I’m having a hard time trying to get my check engine light to go out NOW I had the PO420 code and another code keep coming up I got a diagnostic and the paper work said the was nothing wrong with the catalytic converter but the code keep coming up on the machine and the light won’t go out I had one of the codes fixed but they fixed the wrong one they fixed the one under the truck but it was the one on top so the guy at the place told me to use cataclean to try and clean out the converter he told me to fill it up drive it high speed and run the gas out if the light didn’t go out to fill it up again run all the gas out so my question is even thou I put the cataclean in my truck ran out one tank of gas should I try what oxyclean or just fill up the tank and ran the second tank of gas out? I’m so confused and frustrated. Oh and is there a way to know if a cat. Converter is bad before I buy it. One more question can a 2001 Silverado catalytic converter fit a 2003 chevy tahoe?

I have a 2013 JX35 Infiniti that they say I need to replace my catalytic converters to the time of $2200. Is it possible that it is just CLOGGED, and can I use the catalytic cleaner to see if that will work?

*tune of $2200 yes (per reading the article)