How to Unclog a Catalytic Converter?

The apparatus responsible for controlling toxic gas emissions from a vehicle engine are called catalytic converters. These gadgets are exceptional in controlling local air pollution by converting poisonous fumes from the car engine into safe compounds. Previously you could or maybe you have noticed dark buildings across the road and the reason is not the color of the paint.

The reason for such cases is soot from vehicles and that is why catalytic converters are an amazing addition to the vehicles exhaust structure.

Like all apparatus or rather devices, catalytic converters can crash. Engine failure, lower engine functionality, worse mileage and air pollution are all results of catalytic converters that are not working well. Therefore, when you realize the catalytic converter of your car is not working well, it is good to prioritize it.

Although, normally it is advisable to grab a new catalytic converter for your car, sometimes unclogging it saves you money. Therefore, if the P0420 code is giving you hard time and want to unclog your cars catalytic converter, this article will help you.

How to Unclog a Catalytic Converter

Unblocking the Catalytic Converter

There are various approaches to unclogging catalytic Converters. 

Making the Converter Clean Itself

Before you try other approaches if unclogging a catalytic converter, you should try this approach. Note that this approach applies when the cat-con is not overly blocked and has no loose pieces in it. The process is easy and can be used on any car model and make.

To make the catalytic converter clean itself, look for a cat-con cleaner. You can shop for the cleaner on any auto retail store or online. But, make sure it is compatible with your vehicle. Know which cleaner is best for your car, read the owner’s manual or search for answers online.

Once you have your preferred cleaner, ensure the remaining gas in your vehicles fuel tank is about 15 liters. If the remaining fuel is below 15 liters, refill it to that amount.

Drain the cleaner into the car’s fuel tank. Whether the vehicle is hybrid, uses diesel it petrol, the cleaner will clean the entire exhauster, the O2 sensors and the converter. But catalytic converter cleaners do not mend mechanical defects inside the cat-con if it is overly Clogged, crushed or cracked. The cleaner is specifically for cleaning the cat-con. Mechanical defects need to be handled by a specialist.

The amount of cleaner you will pour into the fuel tank is specified in the user manual. Read the manual to get information on the usage of the cleaner. Try also driving the vehicle at high revolutions per minute about 3500 for many kilometers so as to make the cat-con too hot for burning the blockage.

If possible, drive on a highway. Ensure there are no fluids or oil inside the cat-con to avoid ignition. Additionally, ensure your vehicle is not overheating by inspecting the temperature of the coolant. Once you are done with this process, clear all failure codes available and wait for a new code. If the process is successful, you will not get a failure code again.

Cat-Con Cleaner Not Solving the Problem?

If the cat-con is not too clogged, the above approach will work. However, sometimes the method does not work. In such a case the only solution would be to dismantle the converter and examine it to establish whether it is okay. Note that several problems like leaking in the exhaust system and failed O2 sensors can be the reason for the trouble code P0420. Therefore, it is good to inspect the entire vehicle to be sure the catalytic converter is not failing because of other underlying problems.

Dismantling the Cat-Con for Cleaning

Honestly, the first approach is simpler than the second. And, you should only decide to apply the second approach if you have some experience in it. The method should also be applied when the first has failed to work indicating a severe blockage. The following steps will guide you.

Dismantling the catalytic converter requires you to have several items. It is important you ensure you have them before you start. These items include:

  • Safety gear (goggles and cloves)
  • Pressure Washer
  • A jack (full set)
  • Wrench
  • Piece of Cloth
  • A basin
  • Degreaser

How to Unclog a Catalytic Converter in 7 Easy Steps:

Step 1: Before the Job

Put on gloves and goggles for safety. Ensure you park your car on a level ground and the place is perfectly lit. Get yourself under the car after raising one if its axles using the jack. The exhaust area can be very hot over 370C and so ensure the vehicle has not been running. You cannot remove the catalytic converter immediately you drive it into your compound as it can burn you.

Step 2: Dismantling the Cat-Con

Establish the location of the cat-con. Normally, it is a round or a square box in the end or middle of the exhaust structure. Most likely, its bolts are already rusty. So, get a wrench and start to remove them.

Rust can make it had to remove the bolts and therefore it is advisable to use a lubricant. Sometimes the cat-con is welded on the underside of your car and in such a case you would need assistance from a mechanic.

Step 3. Cross-Check the Cat-Con

You need to be careful here. If the cat-con is entirely burned or crushed, this approach will not be fruitful and the only solution would be to get a replacement. Get a metallic object and hit the box to hear any cracked pieces. You can shake the converter box as well. If you do not hear any sound of cracked pieces, it is time to proceed to the next step.

Also read: Why Does My Car Vibrate When Braking at High Speed?

Step 4: Unclog the Cat-Con

Using the piece of Cloth mentioned previously, wipe the exterior parts of the cat-con to remove the rust dust from it. After wiping, clean the inner parts of the cat-con using a pressure washer to remove any debris or contaminants. Ensure the pressure is medium to avoid breaking parts of the cat-con. Wash through both the inlet and outlet pipes.

Step 5: Soak the Converter

In a large basin, mix a degreaser of your choice with hot water then dip in the catalytic converter for about 50 minutes. Ensure also the catalytic converter does not overstay in the solution to avoid severe effects.

Step 6: Dry it

After 50 minutes, take the cat-con out of the solution and keep it in an open place to dry. If possible, get a towel and wipe it. If necessary, rinse it too before allowing it to dry. 

Step 7: Fix it Back

The catalytic converter is now unclogged and clean ready for reinstallation. You are now sure the process was successful and that the cat-con will give service to your car for some time without failure.

Amusingly, it is not certain that the problem is solved. After reinstalling the cat-con, drive for a while to be sure the issue is sorted. In case there is still a problem, the issue is out of your control and you may have to contact your mechanic or decide to have the cat-con replaced.

The Function of Catalytic Converters

It is paramount to know the work of catalytic converters before you can decide to clean them. When you realize how important these devices are, you will be keen to unclog them the moment you realize there is a problem. So, what is the function of catalytic Converters?

Inside a vehicle’s engine, oxygen combined with gasoline or diesel. In theory, the process should lead to formation of carbon dioxide, steam and energy necessary to move the car. But, in reality the process leads to production of carbon monoxide and nitrogen oxides (life-threatening gases).

The catalytic converter oxidizes carbon monoxide to form carbon dioxide and reduces nitrogen oxides to oxygen and nitrogen gases. The reduction and oxidation processes taking place inside the catalytic chamber are the sources of cleaner emissions from vehicles exhaust. Air pollution as a result of fumes from vehicles exhaust blackens buildings near roads and is harmful to human health.

How to Know a Catalytic Converter gets Clogged

All car owners or drivers are not mechanics. Additionally, it is not possible to see the inner part of the catalytic chamber to know whether it is blocked. Therefore, it is important to know how you can puzzle out a blocked catalytic converter.

Does your car engine misfire because of a rich fuel concoction or any other cause? If this is the case, your catalytic converter may be blocked because engine misfiring melts it leading to a blockage.

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You hear a rattling sound when you are starting your car engine and it takes forever to start when the performance of the engine is poor. This is as a result of clogging in the catalytic chamber. Sometimes you may also smell sulfur or ammonia. A rotten egg smell confirms the presence of sulfur.

You may not notice all these issues. However, if you realize any of them your vehicles catalytic chamber may need cleaning. In case you are not convinced yet, insert a scanner (preferably an OBD-II) to a port on the underside of your cars wheel. Refer to the manufacturers manual in case you do not find the port.

Once you find it, turn in the engine but do not start it. The scanner will give a number that you will search for in the manufacturers manual to learn whether the catalytic chamber needs cleaning.


Note the Following Before you Start

Based on the importance of a catalytic converter, cleaning it is crucial. But, before you start to work on it, you need to take into consideration several things. You do not want to waste your energies and time cleaning a catalytic chamber that can no longer be used and the only solution would be to get a new one. Hence, take note of these things:

Burning of Fuel

Clogging in the catalytic converter can be a result of leaking fuel. Fuel leaks entering the Converter cylinder can get burned causing the converter to block. Clogging as a result of leaking fuel cannot be stopped by any of the methods discussed in this article because the fuel leaks will still cause clogging. So, consider repairing the oil leaks before cleaning the converter. Broken piston rings or valve seals and blocked crankcase airing system are all signs of fuel leak.

Broken Catalytic Converter

If the catalytic converter has some broken parts in the inside, you can know it by hitting the box with a metal. The broken pieces will produce some sound. Such cases need replacement. Therefore, you might have to take your car to your dealer who will replace the catalytic converter.

Overly Clogged

Sometimes, there is too much clogging in the catalytic converter to an extent that your car engine cannot function. In such a case, the only solution would be to replace the converter box or use professional tools to clean it.

Purified Converter

Some parts of the catalytic converter can blow out through the exhauster when cleaning it. You cannot see this without taking it out. Hence, remove the converter and inspect it.

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You now know catalytic converter is very important. Unclogging it is paramount as it can serve for some more time before it is replaced saving you a fortune. The catalytic converters are costly to buy because they are made using precious metals (the reason why they are prone to theft).

Therefore, make sure you inspect it often to ascertain it is functioning well to avoid getting to the market to buy a new one soon. Also ensure you inspect your vehicle frequently to mend any other problem which may lead to the failure of the catalytic converter, for instance, fuel leaks.

When you follow the steps given, you will realize it is easy to unclog your catalytic converter without having to head on to your mechanic and spending your money except when the situation is out if your control. Make sure you begin with the first approach by applying a cleaner to the cat-con. Only proceed to the second approach when the first does not fix the problem.

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