Top Tips On How To Clean Your Catalytic Converter

The catalytic converter is essential to any modern gasoline- or diesel-powered automobile because it removes the harmful byproducts of engine combustion.

Before the emissions exit through the tailpipe, it eliminates particulate matter and other hazardous pollutants. However, your catalytic converter will eventually become clogged with significant carbon buildup and will need to be cleaned or replaced.

Replacing a catalytic converter can be incredibly costly, so cleaning it before considering replacement is the better option.

In this article, we’ve compiled a list of the best ways to clean your catalytic converter to prevent further damage and needed repairs. 

What is a catalytic converter?

The catalytic converter is an exhaust system filter component—a catalytic converter functions by inducing a chemical reaction between the gases passing through it.

Inside the converter, precious metals contained within a hot ceramic case decompose particular molecules. The catalytic converter successfully removes hazardous emissions from the vehicle’s exhaust through this procedure.

This is required because combustion engine pollutants, such as carbon monoxide, are dangerous to human health and the environment.

Catalytic converters are filled with honeycomb-like materials to maximise the surface area inside a tiny box. Carbon and other byproducts of combustion become trapped in the microscopic honeycomb holes over time. This reduces the catalytic converter’s effectiveness.

Identifying the cause of your failed emissions test

At the time of inspection, a failed emissions test is mistakenly identified ninety per cent of the time. A failed emissions test will download any OBD-II fault codes that may be associated with the failure.

Typically, the code P-0420 is discovered, which indicates that the Catalyst System Efficiency is “Below the Threshold.” While a blocked catalytic converter typically causes this, it can also be caused by a faulty oxygen sensor, a crack in the exhaust system, or another half-dozen other problem.

A malfunctioning or deteriorating catalytic converter is one of the typical causes triggering your vehicle’s check engine light. After inspecting your vehicle at a local auto parts store, you may be advised to purchase a new catalytic converter.

Even if your catalytic converter is beyond repair, it is always worth a chance to clean it and restore its functionality. If the catalytic converter is the issue, it is typically beyond the point of being cleaned and must be replaced.

If you’re attempting to determine the cause of this code, you should begin by examining the catalytic converter. Before trying to clean the catalytic converter, there are four things to check.

1. Check if its clogged

Due to excessive carbon buildup in the catalytic converter, a vehicle’s engine may not function properly. It is necessary to first remove the inner catalytic converter, either by using specific tools or by changing the entire catalytic converter, in order to inspect it.

2. Check if any parts are damaged or loose

Internal components of the catalytic converter are likely to be loose or broken if this is the source of your problem. Using a hammer and listening for rattling sounds is a straightforward approach to examining the catalytic converter.

These noises are a sign that something is wrong and needs to be replaced. Remove the catalytic converter and inspect it for loose components, which could cause your exhaust pipe to become clogged and cause your car to stop moving.

3. Check if your catalyst is clean

If your catalytic converter was cleaned from the inside, components might have blasted out of the exhaust pipe and into your car. If you suspect this, remove the catalytic converter and check it. This can be difficult to see without removing it.

4. Check to see whether you’re using too much oil

Excessive oil consumption is another common cause of a faulty catalyst. An internal oil consumption problem, which occurs when oil enters the combustion chambers and is ignited and consumed inside the converter, may have caused your catalytic converter to get blocked.

The treatment may only work temporarily until the catalytic converter becomes clogged again if you have an internal oil leak, in which case you should fix it first. 

Clogged crankcase ventilation, cracked valve seals, and worn piston rings are all signs of an internal oil leak. Crankcase ventilation should always be checked first. This is probably the problem if you see smoke pouring out of your exhaust pipe. The problem will not be solved by cleaning the catalytic converter.

How do I clean a catalytic converter?

If you wish to perform the cleaning yourself, you have two options. One requires first removing the converter, whereas the other does not.

Before we discuss how to clean a catalytic converter, you can prevent the following causes of converter clogging:

  • When driving over rough roads, the ceramic catalyst honeycomb within the catalytic converter can be damaged. The fragments may end up clogging the system.
  • Leakage of oil or antifreeze into the exhaust system is a significant possibility. The leak transforms into thick exhaust fumes when heated, and soot clogs it. Leaks can be caused by a vehicle’s age, broken seals, periodic routine maintenance, or excessive engine oil.
  • Driving short distances will not provide sufficient heat for the catalytic converter to burn the engine hydrocarbons that enter it. This accumulation of hydrocarbons will eventually clog the system.

Using catalytic converter cleaner

Our first method for cleansing a dirty converter requires no disassembly or mess and is inexpensive. This approach also cleans your fuel system and oxygen sensors in addition to your exhaust system.

This method will not work if the exhaust system is excessively unclean or the catalyst honeycomb is broken.

Cleansers for catalytic converters are designed to purify gasoline and diesel vehicles’ fuel, engine, and exhaust systems.

Due to this, they are totally safe for your car, regardless of its make or model. As long as the directions are followed, the catalytic converter cleaning solvent will not cause any damage to your vehicle.

Confirm that this cleaning technique will work by tapping the converter with a hammer or wrench. Hit it hard enough to make it jiggle but not hard enough to dent or break it. If you hear rattling inside the converter, there may be broken components or heavy sediments that can only be remedied by removing and cleaning the converter.

If you do not hear any concerning sounds, continue with the following steps:

  1. Purchase some petrol in a can and an appropriate, high-quality catalytic converter cleaner. Some cleansers are solely effective for diesel or gasoline engines, while others are effective for both.
  1. Add the cleaner to the gasoline tank. The cleaner’s label will provide all directions regarding the amount to pour and the amount of fuel required in the vehicle.
  1. Take your car on a short joy drive. After adding the solution, start the vehicle’s engine and drive it. The cleaner will be circulated while driving to clean the exhaust system. The cleaner’s label will provide the optimal driving time for optimal results.

To get the catalytic converter hot enough to burn away any blockages and residue, we recommend driving with an RPM greater than 3000. It is advisable to shift an automatic transmission into “Sport” mode. 

Please maintain each gear for a bit longer before moving to the next gear while using a manual transmission. Observe the temperature gauge to prevent your vehicle from overheating. If the cleaning procedure is successful, there will be less exhaust smoke, faster acceleration, and fewer engine misfires.

Catalytic Converter Deep Clean

The second method is more physically taxing, but it just requires household cleaning supplies that are non-corrosive. This procedure is not recommended for anybody without prior expertise in disassembling and reassembling automobiles.

You must always consult a specialist beforehand if it is your first time dissembling parts from your vehicle. As with other exhaust components that are exposed to the environment, loosening the bolts is typically the most difficult aspect of the procedure.

Before you begin, you must remember to equip yourself with all the necessary tools and gadgets. To thoroughly clean your catalytic converter, please take the following steps:

  1. Before beginning, allow the exhaust system of the car to cool down.
  1. Raise the vehicle until it can easily pass underneath. Utilise the jack stands to hold the car in place.
  1. Using the oxygen sensor wrench, remove the oxygen sensor(s).
  1. Locate the converter and add penetrating oil to the bolts to loosen them. Have a professional perform the cleaning if the catalytic converter is welded onto or attached to the turbo.
  1. After undoing the bolts, remove and inspect the converter. A loud rattle when the vehicle is shaken indicates that its internal components are in pieces and that a new catalytic converter is required.
  1. If there is little to no rattling, clean the body of the converter and then wash its interior with low pressure.
  1. After pressure washing the input and outlet pipes, combine hot water and degreaser in a container.
  1. Soak the converter in hot water and degreaser solution for no longer than one hour.
  1. After soaking, rinse the device with a low-pressure pressure washer, then allow it to drain until it is dry.
  1. After the system has dried, reinstall it along with the oxygen sensor (s). Then, test the car’s performance by driving it.

If the check engine light remains activated and the code for a faulty catalytic converter is still being read, it may be time to repair or replace your catalytic converter. 


As a user of The Automotive Men (, please note that we participate in the Amazon Associates Program. This means that “As an Amazon Associate, I earn from qualifying purchases.” We are not directly sponsored or endorsed by Amazon, but our website may contain affiliate links that provide us with a commission when you make a purchase through them. Thank you