How to Clean a Catalytic Converter Without Removing it

Eagle's Garage may collect a share of sales or other compensation from the links on this page. This comes at no additional cost to you, and all the prices and availability are accurate at the time of publishing.

If you are dealing with a P0420 code, consider the possibility of an issue with your catalytic converter. Don’t stress about the thought of having to take the converter out to wash it during routine cleanings. Gain the confidence you need by learning ways to clean and check the catalytic converter without removing it. Get to know your vehicle better while saving yourself money and time.     

Things to Consider Before Starting

Ethnic male drivers coping with trouble in car

Before you decide to clean your catalytic converter, eliminate other possible causes of your problem. Consider these common reasons for a P0420 code to be displayed. If any of these potentially harmful conditions exist, removing the catalytic converter for inspection can’t be avoided:

1. Too clogged

Sometimes the catalytic converter becomes so clogged that the engine ceases to operate. If this happens, removing the catalytic converter is your only option. Research the special tools needed for your type of catalytic converter. Replace this part if your current one can’t unclog your current one. Learn the steps for routine maintenance given to avoid a total clog in the future.

2. Check/listen for loose parts

There are times that the internal components of a catalytic converter come loose. Find out if this is your problem by taking a rubber hammer and hitting the catalytic converter at key places. If you can hear loose parts, it is time to remove the catalytic converter for an inspection of all of the internal workings. Tighten the parts so that they do not clog your exhaust pipe and prohibit your vehicle from operating.

3. Purified catalyst

Determine if a former cleaning process actually caused damage to the device. At times, too much force causes the internal parts to come loose and expel through the exhaust pipe. If you suspect this is the case, extract the catalytic converter. Check for any missing pieces or damage caused by this kind of blowout. Repair or replace a purified catalytic converter and take steps to avoid this situation from this point forward. 

4. Oil consumption.

Another possible cause of the problem is your catalytic converter getting clogged due to internal oil consumption. Oil entering the cylinders ignites and burns inside the hot catalytic converter. Locate and fix the internal oil leak before cleaning. Broken valve seals or pistons rings and clogged crankcase ventilation all point to internal oil leaks within the system.  Always check the crankcase ventilation as the first step in your inspection.

How to Clean Your Catalytic Converter Without Removing It

Once you eliminate the possibility of any major underlying causes, learn a system for cleaning your catalytic converter that is economical and effective. Follow these simple steps to extend your catalytic converter‘s life and keep it in top operational condition.

1. Driving Surface

Before beginning the cleaning process, take your vehicle on a routine drive. Drive to a main road or highway and maintain a steady, mid-range speed limit. Push on the brakes repeatedly to see if you notice any change in performance. Before beginning the work on the catalytic converter, we recommend that you drive your vehicle on a flat and hard surface. It would be a wise decision to drive your car on a highway and drive it at a lower speed limit. Apply the brakes throughout the drive, repeating these steps until you notice any change in performance. At times, this process unclogs simple debris that is clogging the catalytic converter

2. Using a cleaner

When choosing a catalytic converter cleaner, do your research. Be sure to purchase a recommended cleaner that is for your type of vehicle. Seek guidance from your car’s manual or a trusted mechanic or car shop representative.

3. Follow the included directions precisely, pouring the recommended amount into your tank.

Drive your car normally to allow the cleaner to circulate through the converter. Watch for the elimination of symptoms like engine misfires, smoky exhaust and poor acceleration. If you see these improvements, you have successfully cleaned your catalytic converter.

4. Using catalytic converter seafoam.

Seafoam for internal vehicle cleaning consists of highly refined petroleum. It does not clean the catalytic converter directly but does clean and lubricate the entire fuel system. This preventive method does not cause harm to your vehicle and is recommended.

Other Related Codes:


Your catalytic converter is a vital part of keeping your car running efficiently with the legal limits of toxic emissions. After eliminating the possibility of significant problems within the system, establish a cleaning routine that is simple and low-cost. Careful maintenance pays off with greater performance and lower fuel consumption. Reward yourself for a job well done by extending the life of your vehicle.

If you like this article, please consider checking these articles below:

Leave a Comment

Our Best Content In Your Inbox