How to Clean Your Catalytic Converter

If you’ve recently attempted to have your emissions checked and was told the vehicle failed, it’s quite possible the root source is a clogged or dirty catalytic converter. The catalytic converter is an emissions-regulated component installed within the vehicle’s exhaust system. It removes particulate matter and other harmful emissions prior to exiting the tailpipe. Eventually, this part will become clogged with excessive carbon buildup and will require cleaning or replacement. However, cleaning your catalytic converter is not as easy as you might think. In fact, it’s not even recommended by professional mechanics or a vehicle manufacturer and if done, may even void vehicle warranties.

If you’re having problems with a catalytic converter and are considering cleaning it, first determine the cause of the emissions issue. Then, decide whether to clean or replace the catalytic converter.

Determine the Root Source of Your Failed Emissions Test

90 percent of the time a failed emissions test is incorrectly diagnosed at the point of inspection. An emissions test will download the stored OBD-II trouble codes that might be related to the failed test. Most of the time, the code found is P-0420 — a generic code indicating that the Catalyst System Efficiency is “Below the Threshold.” While most of the time this can be contributed to a clogged catalytic converter, it can also indicate a failure of one of the multiple oxygen sensors, an exhaust system crack, or about a half-dozen different problems. If the catalytic converter is the problem, the majority of the time it is past the point of cleaning and will require replacement.

If you’re trying to diagnose the source of this code, you should start by inspecting the catalytic converter first. Here are three items to verify before attempting to clean the catalytic converter.

  1. Determine if it’s too clogged: If the catalytic converter is too clogged with excessive carbon deposits, the engine may not run. To inspect the inner catalytic converter, it needs to be removed first.
  2. Check for damaged internal parts: If the catalytic converter is the source of your issue, inner parts will be loose or damaged in most cases. One quick way of checking it is lightly tapping the catalytic converter with a hammer and listening for any rattling sounds. These noises indicate damage and require replacement.
  3. Check for excessive oil consumption: Another leading source of a damaged catalyst is excessive oil consumption. This is usually caused by damaged piston rings, cylinder head valve guides, or fuel injectors. If you notice smoke coming from your exhaust pipe, this is likely the issue. Cleaning the catalytic converter will not resolve the problem.

Consider Removal and Manual Cleaning, or Replacement

Once you’ve determined that the catalytic converter is not damaged or too clogged for cleaning, the next step would be to remove it and attempt to clean it manually. The best method is using water and lacquer thinner. However, there is no proven step or process for cleaning the catalytic converter this way, so you might want to search online for a few additive cleaners, such as Oxicat or Cataclean, that help remove carbon deposits slowly before attempting.

As we indicated at the beginning of this article, cleaning a catalytic converter is not recommended by any vehicle manufacturer. It can damage the internal catalyst and render this mandated system useless. The best solution is to have a professional mechanic replace the catalytic converter.


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John

26 years of experience
620 reviews
John
26 years of experience
Ford Taurus - Catalytic Converter - Houston, Texas
I have used Johns several times for various repairs/diagnosis. Each time he has arrived at or before the scheduled time. He is very knowledgeable about auto repairs and goes about them very professionally. I respect everything that he has done for me, and will always use him for any future repairs. Thanks John!
Ford F-150 - Catalytic Converter - Pearland, Texas
John communicated with me leading up to the appointment and was just what you wanted. He did a great job and represented his company well. Would give him a 10!

Mazyar

7 years of experience
253 reviews
Mazyar
7 years of experience
Lexus LS430 - Catalytic Converter - Duluth, Georgia
I didn’t know what to expect today getting my car fixed. He showed up on time , finished in good timing., and also did a great job. I would recommend him..
Lincoln Navigator - Catalytic Converter - Alpharetta, Georgia
Mark came on time and did exceptional job in replacing my catalytic converters - a job hard enough even for a shop. this is the second time I am using Mark's services and he proved himself as a reliable and knowledgeable mechanic

Marvin

5 years of experience
71 reviews
Marvin
5 years of experience
Acura Integra - Catalytic Converter - North Las Vegas, Nevada
Marvin was on time, very knowledgeable and communicated to me why he wasn't able to do the repairs needed. So I was able to move forward on my repairs. Sincerely, Cindy Mayo CXMayo.cm@outlook.com

Jeshua

6 years of experience
112 reviews
Jeshua
6 years of experience
Ford Focus - Catalytic Converter Replacement - Bradenton, Florida
Jeshua was very courteous, professional and knowledgeable. I was apprehensive in using this yourmechanic.com, but if Jeshua indicative to what I can expect then I'll be using your service from here on out.

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