How Do You Clean a Catalytic Converter Without Removing It?

It is important that our catalytic converters are working at their very best not just for making sure we are being kind to the environment but also to make sure our engines are working correctly. In this article we are going to look at how to clean our catalytic converters without removing the unit.

What Is a Catalytic Converter?

If you grew up during the 1970s and '80s you may recall occasionally driving around in cars with the windows down and smelling a sulfur rotten egg smell from time to time. After exclaiming “What is that smell?” someone in the car likely enlightened you to it being a catalytic converter.

This simple answer doesn’t mean much so let's explore just what a catalytic converter actually is. Basically catalytic converters are devices that capture the emissions from the burning of petroleum. Once captured these fumes are stripped of carbon monoxide, nitrogen oxides and hydrocarbons.

The remaining emissions are then released from the catalytic converter in the form of carbon dioxide (CO2) and Water (H2O). These emissions of course are far less harmful to the environment meaning that the fuel burning process is cleaner.

How Do Catalytic Converters Work?

There are many different types of catalytic converters but they all work along the same principals. Essentially inside these devices there are chemical elements that are used as catalysts. There are reduction catalysts and oxidation catalysts.

These catalysts are metals such as platinum, rhodium or palladium which by the way are not inexpensive. This often means that replacing the catalytic converter is not cheap. The metals are often coating ceramic structures and will trap and react with the carbon monoxide, nitrogen oxides and hydrocarbons as they pass through the device.

Firstly, reduction catalysts such as platinum or rhodium act upon the nitrogen oxides ripping away the nitrogen atoms from the compound. As an example when nitrogen dioxide (N02) passes over these catalysts the nitrogen (N) is ripped away leaving only the two O atoms which for those who might not know is simple oxygen.

The next phase is the oxidation catalysts which might be platinum or palladium. These catalysts with the help of the extra oxygen from the reduction phase take care of carbon monoxide CO and hydrocarbons. Instead of removing atoms they actually force a bond between the O2 and CO molecules turning oxygen and carbon monoxide into carbon dioxide (CO2)

Although excess CO2 is still not great for the environment it is much more preferable to carbon monoxide which can be lethal. Poorly maintained gas burning heating systems for example might produce excess carbon monoxide in your home. The accumulation of this is poisonous and can kill.

Why Is It Hard to Remove a Catalytic Converter?

Some people may be wondering why you wouldn’t remove the catalytic converter for cleaning if it would be easier to do so. The answer is very simple, many catalytic converters are not just simply bolted into the exhaust system, rather, they are part of it.

In order to remove and replace a catalytic converter you literally may have to cut it out of the exhaust system. An interesting note is that catalytic converters are expensive parts which are often targets for thieves. They are not the easiest part to steal but thieves will get under a car and cut the catalytic converter out.

Things to Consider Before Starting

You are sure that the issues with your catalytic converter are due to it being clogged. Cleaning it is sometimes an option over replacing it but there are some things you need to know.

It May Be Too Clogged

If your indication that the catalytic converter is clogged is that the engine will not run then you have a seriously clogged part. As a result you will find that you can not clean this unit without removing it from its place.

You may need specialized tools to clean this overly clogged catalytic converter or potentially you may need to just replace the part. These are tricky parts to clean manually and if you can’t clean them while they are attached the build up may be too advanced.

Listen for Loose Parts

Cleaning your catalytic converter while it is still attached to the car is possible but if there are any damaged or loose parts it may be pointless. Before you try a cleaning process on your catalytic converter, take a rubber hammer and hit the part, listening for any sound of potentially loose parts in the unit.

If you hear any rattling of parts then you should remove the catalytic converter and fix these issues. Inspect the unit to make sure nothing is loose as if they are starting to loosen already they may eventually break free and clog the unit completely.

Oil Consumption

Before you go ahead and clean your catalytic converter you should make sure that the clog has not been caused by burning oil. Engine oil should not be burning in the engine itself and if it does you may see blue smoke from your exhaust.

Before you run a catalytic converter clean you should check your oil levels. If your oil level is low you may have been burning oil. This would indicate an internal oil leak which could mean broken valves, seals or piston rings.

To avoid a rapid recurrence of the blockage you will want to fix any internal oil leak first. If you fail to do so the catalytic converter can become clogged again very quickly and the work you did will have been for nothing.

How Do You Clean a Catalytic Converter Without Removing It?

Having checked for any oil leaks, loose parts in the catalytic converter and ensured that you should be able to clean the part while still attached, you can prepare to do the task. This is a very simple process so read on and we will get the catalytic converter spruced up and working like new.

Obtain Your Cleaner

The easiest way to clean your catalytic converter without removing it is to get hold of a specialized cleaning product. A good choice for this is OXICAT Oxygen Sensor & Catalytic Converter Cleaner.

This is a great cleaner because you simply add it to your fuel tank to make it work. You do need to realize that it only works on slightly clogged units. Heavier clogging will require removal of the part. Also this cleaner will not fix mechanical issues.

Using this cleaner you can not only remove mild soiling that affects engine performance but also clean your O2 sensor and the whole exhaust system. In doing this you will improve the performance of your engine by making the exhaust more efficient than it was while dirty.

Add the Cleaner to Your Gas Tank

You will want to pay close attention to the cleaner's provided instructions and make sure to only add the prescribed amount to your gas tank. This will vary based on your car type and engine so if you use too much you can actually cause damage.

Run the Cleaner Through the System

The cleaner will not do much just sitting in your gas tank so obviously you are going to need to run your engine. This is why a vehicle that will not run due to a severe clog can not be cleaned in this manor. Drive around for a few miles to let the cleaner enter your exhaust system and do its job.

We should note that sometimes you may not need a cleaner at all. Driving your car at high RPMs above 3000 for a long distance may heat your catalytic converter up enough to burn out minor clogs. So if you have a long journey to make on the highway you could use this as your free catalytic converter clean.

What If The Cleaner Doesn’t Work?

As full disclosure we should point out that this method of cleaning will not always work. This is not a fault of the cleaner however as it usually means you have other issues with your catalytic converter or a related system.

Catalytic converter issues could be parts related and require actual repair. They may also be due to an exhaust leak or a faulty O2 sensor. If you are lucky you may have a unit that is bolted on rather than welded so you may be able to remove the part to inspect it more closely.


There is a very easy method to remove slight clogging of your catalytic converter but you must be sure that this is the only reason for your engine performance issues. There is always the possibility of other issues so be aware of this before you waste time with a pointless cleaning.

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