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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Recent Catalytic Converter Replacement reviews

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Mazyar

8 years of experience
464 reviews
Mazyar
8 years of experience
Dodge Caliber L4-2.0L - Catalytic Converter - Fairburn, Georgia
Mazyar is highly skilled, very punctual, and professional. He worked on my car twice and I have been very satisfied.
Dodge Journey - Catalytic Converter - Lithonia, Georgia
My experience was great. Mazyar arrived on schedule, he reviewed the job order with me and made sure everything was correct, his service was A1 he’s professional with a friendly attitude, a few hours later he was done, we test drove it and I was happy my car was fixed. He even checked my oil and tires and prepared a quote before he left.

Michael

36 years of experience
69 reviews
Michael
36 years of experience
Chevrolet Traverse V6-3.6L - Catalytic Converter - San Antonio, Texas
A+++ service and labor was quick. Michael was also knowledgeable and assuring when it came to fixing my vehicle. Would recommend to anyone!
Hyundai Accent - Catalytic Converter Replacement - San Antonio, Texas
He was totally amazing. He explained everything so I understood it all and even gave me some fair suggestions on things I didnt even noticed I needed to get done! I would 150% ask for his help again! Great, Great service and he was fast too!

Patrick

33 years of experience
1408 reviews
Patrick
33 years of experience
Hyundai Accent L4-1.6L - Catalytic Converter - San Marcos, Texas
Patrick was on time and started working on my car right away. He was friendly and trustworthy. I will highly recommend Patrick.

Bryan

2 years of experience
87 reviews
Bryan
2 years of experience
Nissan Altima L4-2.5L - Catalytic Converter - Fort Lauderdale, Florida
Even though I had the wrong part this gentleman still tried to get work done and explained to me everything I needed..and was very professional and on time. I would hope to select him again once I get the correct part. Thanks again!!

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The engine should be checked first to make sure it is not running too rich. If not running rich then the exhaust catalyst (catalytic converters) are bad and need to be replaced.

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