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Lacquer Thinner and Catalytic Converter

edited May 2011 in Repair and Maintenance
Is it safe to clean your catalytic converter by pouring some lacquer thinner in your gas tank and running the engine for about 150 miles as Scotty Kilmer suggests in this video?

The p0420 code came on about a month ago, and it goes off and on intermittently since then - I'm hoping that that means that the problem is fairly recent and, if this lacquer thinner thing works, will get rid of the impurities that are launching that code.

I need some reassurance or some advice before I do this.



  • I can imagine no reason why this would work. Plenty of nutty things on youtube...
  • I don't think it will do any harm, but like texases, I cannot imagine how it could do any good.

    BTW - often on an OBD2 system, a catalyst code will get set when the real problem is that the oxygen sensors are getting old and slow to respond. Do your oxygen sensors have more than 100k miles on them?
  • Lacquer Thinner is mostly acetone..It's a powerful solvent that can damage fuel system components. After it burns in the engine, there is nothing left to "get rid of impurities" in the converter or anywhere else..

    If your vehicle has over 100K miles, try changing the rear oxygen sensor since that's the part that is generating the code...
  • I would never run any amount of lacquer thinner thru an electric fuel pump in the gas tank. Most fuel pump assemblies have mostly plastic components. And if some plastics are exposed to lacquer thinner it melts.

    You do it first:)

  • When you burn acetone (di-methyl ketone) or it's close relative MEK (methyl-ethyl ketone) in your engine, it turns into CO2 and H2O just like gasoline does so I don't see how it has any magic converter cleaning properties. Being aggressive solvents, they might clean your fuel injector nozzles.
  • @Manolito - Yes - well over 100k on the sensors. I'll change it and see if that is the problem.

    I knew it was too good to be true. What about cat cleaners? I haven't really researched them, but are there any that might do the job?

  • edited May 2011
    I didn't expect this to generate that many comments. I have to remember this website in the future!
  • Would the fact that the light goes on and off have anything to do with a bad o2 sensor?
  • "Would the fact that the light goes on and off have anything to do with a bad o2 sensor?"

    --If you had the codes read, you might be able to tell.

  • "--If you had the codes read, you might be able to tell. "

    Actually NO...When you read the codes...if an O2 sensor is bad it'll give a false reading to the OBD-II system. If a cat is bad...the O2 sensor will set the same error to the OBD-II system. You can't tell what's bad by the reading. All you know from the reading is that the O2 sensor is saying somethings wrong. From there you have to do more tests to determine if it's the O2 sensor or it actually is the catalytic converter.
This discussion has been closed.