Using Lacquer Thinner to Clean a Catalytic Converter

Is your car’s check engine light on with a P0420 or P0430 code? Learn whether or not your should try lacquer thinner to clear the code and fix the issue.

When there is an issue with your vehicle’s emissions system, exhaust, or catalytic converter, you may see a check engine light or check emissions light pop up on the dashboard.

Plugging the vehicle into a OBD2 scanner will likely show a code of P0420 or P0430.

These engine codes can indicate anything from a bad catalytic converter to things like:

  • Poor fuel quality.
  • Clogged air intake.
  • Temperature control problems.
  • Issues with the ignition system.
  • O2 sensor problems.
  • Vacuum leaks.
  • Exhaust leaks.
  • Clogged cat converter.

So, to sum all that up, the source of the code may not always be traced to the catalytic converter itself.

Should you use lacquer thinner to clean a catalytic converter?

As stated above, if your vehicle is giving you a P0420 code, it’s possible that it is due to the catalytic converter or something else.

There are plenty of videos, articles, and forum posts online suggesting that you can clean a catalytic converter with lacquer thinner to clear the code.

This lacquer thinner cat cleaning method suggests:

  • Adding lacquer thinner to your fuel tank.
  • Driving the vehicle 100 to 150 miles running the engine a high RPMs throughout the trip.

Many have claimed this does the trick and the code goes away.

So, should you try the lacquer thinner method for your own vehicle? No, you shouldn’t.

While you may be able to clear the code, you run the risk of doing more harm than good.

For one, this method may not be solving the route issue of the check engine light in the first place. While it may be able to clean out some gunk that’s built up in the catalytic converter, it’s not going to be a fix all solution.

More importantly, introducing lacquer thinner to your fuel system and engine can cause further issues itself.

Plastic seals, rubber parts, and other components in your fuel lines and engine may be irreversibly damaged by introducing lacquer thinner.

At best, using lacquer thinner to clean your catalytic converter will delay the P0420 code for a while, at worst, you’re going to do more damage to the vehicle.

As a rule of thumb, don’t rely on magic solutions to fix problems in your vehicle. It’s best to trace down the root cause of an issue and fix it properly or replace the part.

For questions you may have about vehicle repairs and maintenance, consult with a qualified, licensed mechanic who is familiar with your make and model.