How to clean a catalytic converter

The catalytic converter is undeniably an essential part of a vehicle. The converter has an effect on the performance of your vehicle, and it reduces tailpipe emissions. Without an effective converter, your vehicle may start to suffer from slower acceleration, poor fuel efficiency, lack of power, and unpleasant odors. That is why it is important to clean your catalytic converter if it is underperforming due to an internal obstruction.

To clean a catalytic converter, you can either add a cleaner to your gas tank that'll work its way through the exhaust system or perform a more comprehensive wash that requires the removal of your converter. Whichever route you take, it is important to remember that cleaning your converter might be a cost-effective decision but is not always the remedy if it's not working optimally. Sometimes a replacement is the only solution. Edmunds walks you through how to clean and maintain yours and how to recognize when it's time for a replacement.

How do you clean a clogged catalytic converter?

Because a catalytic converter is in charge of removing exhaust fumes, clogs may emerge over time. Aside from your vehicle exhibiting lackluster performance, your check engine light might turn on after the catalytic converter's sensors register the issue. We suggest you clean your catalytic converter as soon as you're certain that's the problem to avoid serious damage that may require a costly replacement.

One way to clean your clogged or dirty catalytic converter is through additives or cleaners. This method is perhaps the easiest because it doesn't require much skill to complete. You will not need to remove anything but the gas cap on your filler neck. You add the converter cleaner to your gas tank and it then mixes with your fuel — there must be some fuel remaining and the amount may differ depending on the cleaner of choice, so read and follow the instructions for the product you purchased.

Essentially, these cleaners contain detergents and solvents that remove contaminants and break down buildup produced by the combustion process. Which converter cleaner to use can depend on your specific engine, but there are various universal cleaners that work perfectly well with any gasoline engine, and some that are even OK to use on diesel engines. We recommend you do some research to verify which converter cleaner is the right one for your vehicle.

Another way to clean your catalytic converter requires the removal of the part. This option obviously entails more time and mechanical expertise. You also run the risk of damaging the converter in the removal and reassembly process. There are three options to try, though none is guaranteed to work:

Soaking: One method to try is submerging and soaking the catalytic converter in a soapy water solution. A dedicated oil or degreaser product will probably work best, though you might also try dish soap. Add your cleaner to a sufficiently large bucket of water where the converter can fit. Submerge the converter into the bucket and let it sit overnight. The next day, pull out the converter and ensure that the converter is free from any debris before letting it dry completely.

Chemical cleaning: For this method, try spraying a chemical cleaner (such as carburetor cleaner) through the interior of the catalytic converter to remove the clogging deposits.

Pressure washing: You can also try using a pressure washer to spray water through the inside of the cat to remove stubborn deposits, but make sure that the pressure washer's setting is at its lowest to avoid damage to the catalytic converter's internal structure.

Are catalytic converter cleaning products worth trying?

Catalytic converter cleaning products are definitely worth trying. Using a cleaner can potentially keep you from spending some serious dough on a cat replacement. These cleaners are specially formulated with solvents that help to clean a catalytic converter, in addition to cleaning other components like oxygen sensors and fuel injectors. One of the biggest upsides of these products, aside from being very easy to use, is that they're inexpensive. Most cleaners run under $30 and you can purchase them from most auto parts stores or online.

What to avoid while cleaning a catalytic converter

First and foremost, we suggest you verify that cleaning your catalytic converter is a viable solution to your problem. If you are going to use additives, make sure you use the correct one for your vehicle. As previously mentioned, there are some cleaners that are universal and can be used on any engine. Before adding the additives to your gas tank, check that there is sufficient fuel remaining. If you decide to remove the cat and perform a deeper wash, double-check that none of the chemicals you intend to use are corrosive. 

If you're using a pressure washer, confirm that it is set to its lowest/softest setting because the high pressure can break the internal components. When reattaching the converter, whether by simply bolting it or welding it back on, ensure that everything aligns without gaps between parts.

Is cleaning the catalytic converter always effective?

Unfortunately, cleaning your catalytic converter does not guarantee it'll work effectively afterward. If your converter is defective, cleaning it will not make an impact and any symptoms present before the cleaning process will return. In the end, if nothing works, a replacement is the way to go. We do advise you to seek professional help if you're unsure about anything in this whole undertaking.

What causes a catalytic converter to get clogged?

We've already established that a catalytic converter plays a crucial role in your vehicle's emission system. However, with time catalytic converters may become dirty and even clogged. 

A catalytic converter can become clogged with carbon deposits, which are a byproduct of burning gasoline in internal combustion engines. In some cases, if there is incomplete combustion in the engine, the unburned fuel is forced into the exhaust system, which can create carbon buildup inside the converter and restrict flow. The honeycomb structure within a converter can also become contaminated with soot built up by coolant or motor oil that has leaked into the exhaust system. Needless to say, a catalytic converter relies on the performance of other components to have a healthy and long-lasting life.

In summary

Cleaning a catalytic converter is easier than it seems, and the outcome can make all the difference in your vehicle's performance. In addition, maintaining a clean catalytic converter can save you a lot of money.

This story was produced by Edmunds and reviewed and distributed by Stacker Media.