If you have recently tried to have your emission inspected and was told the car failed, it’s quite possible the root source is a clogged or dirty catalytic converter. The catalytic converter is an emissions-regulated component mounted within the vehicle’s exhaust system. It takes particulate matter and other harmful emissions prior to exiting the tailpipe. Eventually, this component will become clogged with excessive carbon buildup and will need cleaning or replacement. However, cleaning your catalytic converter is not as easy as you might feel. In fact, it’s not even recommended by professional mechanics or a car manufacturer and if done, may even void car warranties.
If you’re having issues with a catalytic converter and are considering cleaning it, first know the cause of the emissions issue. Then, decide whether to clean or change the catalytic converter.
Know the Root Source of Your Failed Emissions Test
90 percent of the time a failed emissions test is often incorrectly diagnosed at the point of check. An emissions test will download the stored OBD-II trouble codes that might be associated with the failed test. Most of the time, the code found is P-0420 — a generic code showing that the Catalyst System Efficiency is “Below the Threshold.” While most of the time this can be added to a clogged catalytic converter, it can also show a failure of one of the multiple oxygen sensors, an exhaust system crack, or about a half-dozen different issues. If the catalytic converter is the issue, the majority of the time it is past the point of cleaning and need replacement.
If you’re thinking to diagnose the source of this code, you should begin by inspecting the catalytic converter first. Here are three items to verify before attempting to clean the catalytic converter.
- Check if it’s too clogged: If the catalytic converter has become too clogged with excessive carbon deposits, the engine may not run. To check the inner catalytic converter, it needs to be first removed.
- Inspect for damaged internal parts: If the catalytic converter is the source of your issue, inner components 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 show damage and require replacement.
- Inspect for excessive oil consumption: Another leading source of a damaged catalyst is excessive oil consumption. This is often caused by damaged piston rings, cylinder head valve guides, or fuel injectors. If you observe smoke coming from your exhaust pipe, this is likely the issue. Cleaning the catalytic converter will not resolve the issue.
Consider Removal and Manual Cleaning, or Replacement
Once you’ve known that the catalytic converter is not damaged or too clogged for cleaning, the next step would be to take it out and attempt to clean it manually. The best method is using water and lacquer thinner. However, there is no particular step or process for cleaning the catalytic converter this way, so you might want to search online for a few additive cleaners that help remove carbon deposits slowly before attempting.
As we noted at the beginning of this article, cleaning a catalytic converter is not recommended by any car manufacturer. It can damage the internal catalyst and render this mandated system useless. The best solution is to have a professional mechanic change the catalytic converter.