How to unclog and clean catalytic converter without removing it

A catalytic converter is both an essential part of your car as well as for the environment. But with the amount of dirt it sees daily, it must be cleaned at some point. It can be tough, and that’s why we bring you the perfect guide. Here’s how to unclog and clean catalytic converters without removing them.

What is a catalytic converter?

It is what it sounds like. It’s a super important part of any motor vehicle. Its job is to convert the released gases from the engine into safe emissions. It ensures that only harmless gases like steam are released into the air. It occurs due to a simple redox reaction.

What happens if you don’t fix a catalytic converter?

There can be several reasons for a bad catalytic converter. Here are some of the possibilities:

  • Engine running rich – this means lots of unburnt fuel is entering the exhaust pipe, eventually causing the converter to get blocked.
  • A leaking head gasket – A broken head gasket will mean that the coolant and oil are mixing. When this exits through the exhaust into the converter, it will be a goop-like mixture that will cause it to become clogged.
  • Worn-out piston rings – These will cause oil leakage and increased exhaust smoke, which causes clogging.

If you don’t fix the converter in time, here’s what will happen:

2015 Infiniti Q50 Oem Catalytic Converter

Reduced acceleration

Acceleration requires lots of fresh air from the outside to aid in the combustion cycle. But this is impossible if the converter is clogged and filled with unreleased exhaust fumes. Eventually, you’ll notice the acceleration reducing or having difficulty speeding up.

Failed emission test

If your vehicle isn’t releasing safe gases, you’re in the negative for a safe emission test. You’re releasing pollutants that aren’t being broken down into harmless compounds by the converter. It is going to cause you a serious surcharge.

Harmful for environment

If your car is not releasing safe emissions, it’s polluting the environment every time you drive. It is the last thing we need with rising temperatures and global climate change.

Bad fuel efficiency

You’ll eventually notice that more fuel is being used than normal. It is because exhaust fumes aren’t being released, thus not allowing any space for fresh air. Fresh air is necessary for fuel burning. What ends up happening is that more fuel is spent on average.

catalytic converter

Will a clogged catalytic converter cause a loss of power?

Yes, it’s likely. If you’re going uphill or speeding up and suffering from loss of power, the cause is likely a bad converter. The vehicle only loses power when the fuel isn’t burning properly due to a lack of fresh air for combustion. The catalytic machine’s job is to let gases out and fresh air in.

How to fix a catalytic converter without replacing it?

You can do a couple of things to fix minor issues in your converter. Minor issues will mean you will not have to consider replacing or removing the converter.

Speed it up

Suppose your car isn’t used too much. In that case, the catalytic converter may not reach the optimal temperature to be heated up, causing it to trap gases. Drive your car super hard and let the temperature rise. The exhaust fumes should exit through safe emissions and clear the way.

Clean it up

The amount of work a catalytic machine does will cause it to get dirty. You can take it out mechanically, and pressure washes it to remove all the dirt. Alternatively, you can soak it in a degreaser for several hours and watch the magic happen.

Fuel additives

These are great if you want a quick way to get the job done. Add a solution like Cataclean to your fuel and drive your car for 15 minutes. It will clean up the exhaust pipes and engine for good. You can also use lacquer thinner if you want to go for something cheaper. Make sure your tank is half full and fill it with a gallon of the stuff. Let the car idle in the driveway for about 2500 RPMs.

Can a catalytic converter be cleaned?

Yes, certainly. It can be cleaned in both ways, by removing it and without removing it too. You will need some technical know-how to remove the converter in the removal method. Pressure wash it after the removal, and you’re good to go.

If you want to go the non-removal way, you must add a cleaning additive to the fuel like Cataclean. Once this is done, simply drive your car around for 15-20 minutes, and you’re done!

How to clean a catalytic converter without removing it?

A super quick method to get the engine nice and clean in less than 10 minutes. Here’s what to do:

Find a good fuel additive

There are quite a lot of products in the market for this purpose. Some are specific to fuel types, but most aren’t. Get enough to clean at least 2-3 times, and it should last you more than a year as they aren’t cleaned that often. Cataclean and Seafoam are some good ones.

If you can’t find anything near you, go for a simple lacquer thinner which should be easily available near your nearest hardware store.

NameSevere Catalytic and Exhaust Treatment Cleaner Fuel Additive
BrandDura Lube
Country of Origin‎USA
Item Form‎Liquid
Product Dimensions‎2.62 x 2.62 x 9.12 inches
Size16 fl ounces


  • It’s very easy to use.
  • The price is very reasonable.
  • You can save some money if you choose the 6-pack.
  • It works surprisingly well.


  • The packaging is not great.
  • It’s not a miracle cure.
  • We weren’t familiar with the company.

Fuel tank

Open up the fuel tank. Make sure your tank is half-full and not full. There should be enough space to add the solution and yet enough to drive around for a couple of miles.

Pour in the amount mentioned in the manual. Too much will cause an adverse effect, while too little will not clean properly.

Drive it around

Now hop inside the car and start driving it around. You will feel a difference in the running instantly. Make sure the RPMs reach at least 3000, but the car doesn’t get too hot. The job should be done in about 15 minutes.

If you’ve used Lacquer thinner, you will need to drive around longer for 150 miles, or you can leave the car on idle for 2500 RPMs in the driveway. The effect should be the same.

Here’s a Lacquer thinner.

Item Weight‎7.74 pounds
Manufacturer‎WM Barr
Package Dimensions‎10.16 x 6.81 x 4.29 inches


  • It’s easy to use.
  • It’s great quality.


  • A fuel additive is more effective as it’s made for the purpose.
  • Make sure you use it correctly.
  • It’s a pretty big container
Lacquer thinner
222 Reviews
Lacquer thinner
Here's a Lacquer thinner.

Can a catalytic converter unclog itself?

Usually, we would say this is tough. But if your car doesn’t get driven around much, it could be that the converter never reaches the right temperature to do its work and thus gets clogged.

Thus one way to unclog itself is to hit the highway! Yes, you will need to drive at around 2500-3000 RPMs and keep the momentum going for at least half an hour. This way, the converter should heat up enough to do its job and unclog on its own.

But if this doesn’t happen, you will have to resort to other solutions like fuel additives or removing and washing it.

How to test a catalytic converter?

2016 Focus St Downpipe Catalytic Converter

There are several ways to test whether this part is clogged or gone bad. Here are a few:

Using a pyrometer

  1. Turn on the engine and let it idle at 2500 RPM for several minutes.
  2. Take a pyrometer and record the temperature of 50mm before and after the converter.
  3. The outlet temperature should be 40 degrees Celcius hotter than the inlet. If it is not, you know it’s faulty.

Using a vacuum gauge

  1. Put the car in park or neutral.
  2. Remove the vacuum hose from the brake power booster and connect the vacuum gauge to the hose.
  3. Now start the engine and let it idle for 15-20 minutes. It should reach a high temperature.
  4. At this point, the reading should be 18-22 in Hg.
  5. Let the speed go to 3000RPM and watch the needle go up, but it should go back to the previous reading. If this doesn’t happen, you know the converter is clogged.

Using a back pressure gauge

  1. Let the engine idle for about 20 minutes, or take the car for a drive around the neighborhood.
  2. Park in the garage and remove the oxygen sensor. For this, you will probably need a jack to raise the car and apply brick or wooden blocks at the wheels.
  3. In place of the sensor, apply the pressure gauge instead.
  4. Now start the engine and check the gauge reading.
  5. The pressure reading should be between 0-3psi.
  6. The reading should be between 1 and 3 psi when increasing the speed. But if this goes up to 8 psi, you know you’re in for a bad converter.

What are the signs of a bad catalytic converter?

There are some signs to spot a bad catalytic converter if you haven’t already. Here they are:

Engine misfires

An engine misfire will mean a catalytic converter that’s gone bad. Misfires happen when the engine isn’t burning fuel completely. When the engine doesn’t get enough air to complete the combustion process, the engine leads to a misfire.

Check engine light

The check engine light is usually the first thing to watch out for. It indicates something is wrong with the engine, and you should check the converter first if the other signs are also present.


Is there dark grey or black fumes releasing from the exhaust pipe? It is a problem when the job of breaking down harmful compounds into harmless ones isn’t done properly.

The bad fumes are a big sign you must clean or replace the catalytic machine.

What’s inside the catalytic converter?

This part of a car converts harmful emissions into safer and cleaner ones. For this, the gases need to pass through effortlessly. It is aided by the honeycomb structure that we find inside. It is made from ceramic and covered with various precious and rare metals. The metals act as catalysts in the redox reaction that occurs with the gases.

The metals range from palladium, rhodium, nickel, and platinum. The amount of platinum is usually anywhere between 3-7 grams.

The outer structure is made from a heat-resistant substrate.

Driving with a bad catalytic converter, can you do it?

There’s no end to the things you can and can’t do, but everything has consequences. Here’s what will happen:

  1. First off, problems will occur using the power. Going uphill, you’ll probably lose power. Or, while speeding, you’ll wind up not doing so.
  2. Poor fuel burning will lead to more fuel being used than normal. With rising fuel prices, you might even end up burning more fuel than it’ll cost to replace the converter altogether.
  3. Eventually, you’ll end up choking the car with exhaust fumes, which will mean you won’t pass the emissions test. It means it’s not legal to be driving that car. Eventually, you will have to get the converter checked out and repaired in the end.


Here are some common questions about car parts you’d want to know too!

Can a catalytic converter cause a misfire?

Yes. Incomplete burning of fuel will cause a misfire like no other. Incomplete burning is the effect of having a clogged catalytic part. Having frequent misfires is not a good thing for your car. You should get your vehicle checked out and cleaned thoroughly; if needed, the part should be replaced. There are some ways you can clean the part without removing it yourself. If you want a thorough cleaning, get the part removed and pressure washes it or soaks it in a degreaser.

How long does it take to replace a catalytic converter?

This part is quickly accessible, so you won’t need to disassemble the whole car. The mechanic will remove it easily and replace it soon. We’re averaging an hour or two for the whole procedure.

If you’re looking at just cleaning the converter, this will take just half an hour with a fuel additive.

Is a catalytic converter worth replacing?

Yes surely. This part plays a major role in your motor vehicle. First of all, it’s the only thing that will make you pass the emissions test, which will ensure you can legally drive the car.

Secondly, you’ll have poor acceleration and bad fuel burning if you don’t replace it soon. You will end up paying thousands on gas alone, and it’s better to spend on that part instead.
Most importantly, it is also super unsafe to keep driving a car that can have a misfire or be stopped for illegal driving.

Can you clean the catalytic converter with vinegar?

Yes, if you can remove the part entirely from the car. Remove the part and soak it overnight in a vinegar solution to hollow out a catalytic converter. By morning you should notice the carbon is gone, and a shiny new part is left in the dish.