Testing a Myth: Will Lacquer Thinner Clean a Dirty Catalytic Converter?

[@Doomed3000]

Just because you have a code for catalyst efficiency does not mean that the cat is clogged. The downstream or upstream 02 sensors could be reading incorrectly. The cat could be overhead, or it could have hot or cold spots. If the cat is clogged, it needs to be replaced. You won't fix it by pouring stuff in your fuel tank, and you could cause damage to components in your fuel system. The best way to diagnose a cat issue is to graph the 02 sensor voltages. The upstream or before cat sensors should switch back and forth quickly from .1 volts to .9 volts. The downstream sensors should stay at about .45 to .5 volts and not switch. If the downstream sensors are switching like the upstream sensors, it is a good sign that the cat is not working and needs to be replaced. If the upstream is not switching, it is most likely a sensor. A thermal imaging camera can also help to find hot spots or a clogged cat. The outlet side of the cat should be hoter than the inlet. If it's not, the cat is most likely not working. If there are hot spots, it indicates the cat is clogged at that spot. Hopefully this is helpful.

[@JLAGAN49]

450 millivolts not 4.5 volts!!!!!!

[@Doomed3000]

@@JLAGAN49 Thanks for correcting my mistake!

[@dashonh1214]

Lol I swear it’s just Toyota things especially in gs’s

[@staydownkillen2087]

Af sensor voltage for this year is supposed to stay a bit about 3. This is a wide band sensor not a narrow band. Don’t throw out false info to everyone, it can confuse a lot of people

[@Krankie_V]

This toyota has an afr sensor upstream not a regular o2

[@stackinpaper]

worked on my friends 2002 chevy tahoe. he was about to buy a new car since he wasn't willing to spend that much on replacing the cats. i told him to put a gallon of lacquer thinner when you have half a tank. after it went thru he filled it up tank. about 3/4 tank the light went off and was able to pass smog the next month. still driving to this day. its been about 8mos

[@DEATHWISHVQ]

It’s amazing how people think spending $5000 (educated guess) on a new old car, to avoid replacing a $250 part. It’s like saying oh shit my car needs new tires fuck that’s gonna be 600 lemme buy a new car.

[@stackinpaper]

@@DEATHWISHVQ right?!? There are people out there that just get bored of their car so anything that goes wrong with it is an excuse to buy a new one. My niece did that. Headlights worn and dim and told us it’s a safety issue. I found a pair of new headlights on Amazon $500 and said I would replace them if she ordered them. A week later she pulls up in a new car smh

[@rine413]

@@DEATHWISHVQit’s 276 for my front one and 395 for my rear one. Not sure I trust going this route cause I don’t wanna fuck shit up more, but I get why people do it. They think the car is becoming a money pit.

[@ron8935]

It's done by rinsing out the catalytic converter in a lacquer thinner bath..... And it works great....

[@Mirici1]

The people putting random chemicals down their gas tank are insane. You can damage o rings and components

[@ozb10]

​@@Mirici1have you heard of lacquer thinner causing that?

[@JohnSmith-xx1lx]

He said BATH PAY Attention.@@Mirici1

[@keebler_137]

When using thinner, you should drive for 150+ miles trying to keep rpm around 2500-3000 to burn out impurities and clean it

[@peterb5706]

Move to Florida where there are no inspections.

[@carlgauthier7219]

Remove the cat , put it in a bucket with caustic soda , put a lid , add boiling water , close the lid , leave it here 2 days , brand new nanocoated cat 🐈‍⬛

[@pontiffury9451]

You're supposed to drive for a few hundred miles before determining if it helped or not

[@anilwallace5080]

He drove a entire tank in a toyota. Probably drove 400 miles or so

[@SuperJ213]

@@anilwallace5080 He drove 18 miles and reported. He needs to run the gas tank down. Ideally, he would report after filling up again, provide a report, and then give us updates after a few tanks.

[@michaeleckhart8657]

He added much fuel. His ratio was off.

[@outdoor044]

​@@SuperJ213Running the tank empty only mattered when there was a good ratio of thinner in the tank to clean the cat. Running the next tank down isn't doing anything to help. The first tank that he ran empty took him 177 miles which seems really low. I've heard 300 miles is needed, so what that means is he maybe should have tried another tank with thinner after the first time and get more miles with the cleaning solution. Who knows, this solution is hit and miss for people. Mostly miss from what I've seen. I would try it though before spending big money on an old car.

[@frederickpauly2586]

​@anilwallace5080 half tank to 1 gallon of thinner. He used a full tank. He should of used 2 gallons of thinner for a full tank

[@christerry3432]

Take off the upstreaknoxygen sensor that's on your exhaust manifold. Spray the seafoam spray into and down the manifold. Let it sit for at least 20 minutes and it will do the trick

[@jalil2352]

How has this faired for you so far? I'm curious to do this.

[@christerry3432]

@@jalil2352 I've met a lot of mechanics that do this and have been successful

[@KollynJ]

Has this been successful for a lot of people and is im assuming it’s a somewhat temporary solution

[@electric8668]

Should have only had half a tank to start.

[@harms5846]

Try blowing the car up, should fix the check engine light being on

[@Micheal1075]

Horrible advice, the light is glowing brighter than ever

[@ralanham76]

The check engine light never goes away on Toyota, but you can keep driving it anyways.

[@timmusician5060]

I thought you were going to say to blow into it like a Nintendo cartridge 😐

[@Dansk55]

​@@Micheal1075 😂

[@A_Cowboy_called_JackRabbit]

​@@timmusician5060 I tried that too. Now my car won't start at all.

[@anthonyvarzino1094]

This trick got my Corolla through inspection for three years. It would keep the light off for about half a day lol

[@OLIVER949OC2]

Its like beating the drug test 😂

[@jdwool08]

Sounds like a great loop hole.

[@HugoStiglitz89]

You drove 30 miles 😂 try using the whole tank

[@Krankie_V]

Try replacing the air fuel ratio sensor and the downstream oxygen sensor, with OE parts, before just assuming it's a bad cat. Even if replacing the sensors does not fix the issue, they should be replaced along with the cat anyway

[@Lex-cm9dw]

It’s probably an o2 sensor. Common issue on Toyotas.

[@bluor3713]

That's what it was on my Honda.

[@BillyBob-op6lg]

That throws a different code

[@MarkHorn-td9mh]

I'd say p0420 converter efficiency is just about as common as Toyota A/F sensor fault

[@onthetarmacinc.4210]

Scotty Kilmer

[@Acanofalconpunch]

Remove the O2 sensors from your catalytic converters and pour it down that way it worked for me.

[@sterlingwitherspoon5709]

Ain't no way lol😂

[@BRANDONGONE92]

How long did you let it sit there before you started it ?

[@timin770]

Sounds like a recipe for a car bomb

[@bugayev]

VERTIRLO POR EL AGUJERO DEL SENSOR DE OXÍGENO? BUENA IDEA

[@joerivera45]

Put a drilled out spark plug spacer on the down stream 02 clear it and run it.. see what happen oh Napa or autozone advanced auto has the spacers you need

[@craigkeller]

Additive by the name of Cataclean worked for our Mercedes. 30$ or so at NAPA.

[@johnbelwell2461]

I've used lacquer thinner (toluene) as cheap gas substitute in many vehicles and i can assure you it burns cleaner than the gas mix (gas also contains toluene) has more octanes causes no damage and cleans carbon, only objection is i haven't used it long enough to check for dry hoses etc and in unadjusted carbureted bikes it's hard as heck to start in a cold morning, fuel injection adjusts its self with no problems. Not sure if it helps with cats but toluene exhaust gases passing through cats are no different than gasoline ones it might just burn cleaner and trick o2 sensors.

[@MakeItWithCalvin]

My 96 Civic cleared Cali SMOG with flying colors but 3 months later gave me a similar "catalyst below efficiency threshold." 2x new O2 sensors later, it runs just fine! I am with the crowd saying it is more likely than not that the oxygen sensors are misreading due to age than the actual cat being bad. Also, I feel like a lot of these "cleaners" may work for a slightly dirty one, but if it is just coked up like crazy, no amount of cleaner will solve that!

[@michaelwoods3850]

Goodbye injector seals

[@jonathanmilland2867]

Worked for my '13 accord twice. First time was at 30k miles and second was at 190k

[@rolls_8798]

damn, I know Hondas are supposed to last a while, but you've been rocking one from the 1300s?

[@toob247]

30k miles? The cat wasn't bad. Mayne a bum o2 sensor. Burnt fumes don't clean anything.

[@jonathanmilland2867]

Still have original sensors installed

[@jonathanmilland2867]

@@rolls_8798 nice pickup

[@michaelknight1980]

Did you put it with a full tank? I would think less gas would be more concentrated

[@D-Slowpass]

I used Rislone cat cleaner and the code went away😅

[@wilyceyote]

I did it to my 2000 Mazda protégé I only put 5 gallons to 1 gallon of lacquer thinner then drove it The Code 420 went away

[@homeguardster]

update?

[@wilyceyote]

@@homeguardster has not came back on either for over eight months now

[@jacquesunu]

I have tried it many time and it does work .Run the car some more .

[@one2toomany]

It worked in my truck for approximately 6 months, then the code came back on. I cleared the code, and have yet to see if the code returns.

[@elmerfisher1050]

It does so work, you diluted it too much, we tried it on a 2008 Dodge Caravan, 1 gallon to half a tank and it worked, however you have to get the smog test as soon as the light goes out because it may come back on in a few days

[@L2design]

OMGGG 2001 FORD EXPLORER PUT 1 GALLON LAQUER THINNER AND SEAFOAM AND 2 CAT CLEANERS IN 1/4 TANK... IT WORKS BABY!!! I CAN GO UP THE HILL NOW...AND MY GAS MILEAGE WENT UP FROM 12 TO 13 MILES PER GALLON. YIPEEEEE ORDERED TWO O2 SENSORS AND WILL SEE IF I PASS SMOG IN A WEEK THANK YOU MR KILMER YOU SAVED ME $2000

[@buddymac78]

I am a Skeptic at heart but tried LT at 1/2 tank in my 2.4 Camry and it cleaned a blocked Cat. Drove it 100 Miles the Code was Gone. Passed CA smog the Same Day…

[@DEVILDOG1964]

I TRIED CATACLEAN AND REDLINE AT THE SAME TIME LESS THAN 1/2 TANK F 150. IT TOOK A WEEK FOR THE LIGHT TO GO OFF IT DID FOR 10 MONTHS BACK ON AGAIN. GOT TO GET MY TANK DOWN TO 1/4 FULL.10/28/23

[@christianlail7266]

Test for back pressure. Cheap harbor freight fuel tester will do. If no back pressure add a spark plug defouler on the end of our O2 sensor then screw it back into the cat. May have to drill out to get the end of the O2 sensor to go all the way in

[@elmerfisher1050]

Advance auto also sells them and yes, they do work really well, and yes, remember to drill out the end of it because I ruined the threads on my O2 sensor, you don’t have to drill it out if you buy one that is long enough, advance sells two different lengths

[@professionalbaddass]

1 gallon thinner to 4 gallons fuel..worked great so far 05 honda 314000 miles

[@pigswillbepigs]

Ps if you take the cat off smash the inners out. 👍 worked for me.

[@billsauer3164]

That's all fine and dandy if you live in a county where you don't have to have your car inspected. If you live somewhere where you have to have your car inspected yearly in order to get your sticker that will not work. Cutting the biscuit out of your converter will not turn your check engine light off

[@pigswillbepigs]

@@billsauer3164 not my fault you chose to live in California. Now get back in ya Prius. 😂

[@GweGwe-lu9ob]

Honestly I’m thinking of just cutting mine it’s a waste of money it’s literally cheaper to Straight pipe my truck and cut the cats and muffler them to have a useless part that makes my truck run like ass

[@georgesaucedo7929]

@@GweGwe-lu9obI’m the same way my trucks has been lagging so much and makes a noise from the cats at a stop, been thinking of just straight piping it instead of trying Lacquer thinner and ruining some engine component

[@GweGwe-lu9ob]

@@georgesaucedo7929 yeah man I just straight piped my 2002 cammed 5.3 and it was well worth it and it is pushing like 360 right now next up a tune.

[@charizmah5]

buy a obd2 scanner to eliminate the guessing stats

[@nathanhardin8530]

I tried this on my 2015 F-150 with a 2.7 ecoboost. The passenger cat was giving me a code. I already had the driver side cat replaced. It did not work for my truck. I have tried about four separate times with laquer thinner, and the code comes back after I reset it.

[@brandiszablewski5880]

So how is your vehicle running now? How many miles has it been? I have been told this can cause significantly worse damage to the engine and other components of the vehicle

[@Mxcarnivoro]

It worked on my 2008 expedition EL. 1 gallon of laquer thinner for 10 gallons of gas. Codes cleared

[@LMB222]

My Honda's fuel pump died after I tried this.

[@kelsycunningham8452]

Too strong a solvent for the in tank pump.

[@Carl-fl6wl]

2014 Ford edge I got cat effiency code ..I ran cat cleaner it worked I was spending too much on the cat cleaner ....I poured lacquer thinner and I poured a quart or so of it the light went away I did not clear it ....using higher octane gas the light stays away I run crappy gas in comes back on ...thinner works for me

[@cesarzavala1781]

If you have a Nissan Altima good luck getting that back catalytic converter😅

[@leonardoneil8768]

Your supposed to have half a tank of gas they put applicant in then drive 200 or let idle for a hr ur choice then Wala clean catz

[@rolls_8798]

Toyota back at it with the dpf and cat issues I see

[@feliponii9940]

Thanks for trying and for the results

[@robertchandler7733]

Glad it still runs. A FOR SALE sign woulda been even cheaper and save much more time.

[@rbisthatyou]

Ratio off you’re supposed to use half a tank gas not fill he car all the way up

[@user-yu9zr2hu2r]

Have you tried CataClean?

[@JM-rf3lv]

It took awhile and a tank or two after lacquer for my light to stay off. It been almost a year for good measure I’m doing it again

[@afroandrew816]

Yea 3 miles is definitely not enough to say it didn’t work if it comes on after 100 miles then it probably didn’t work

[@cycleguy666]

Could be a lazy or slow oxygen sensors too!! Try cataclean first then you have to do oxygen sensor testing!!

[@LygerTheCLaw]

the big guns? try injected water. you just have to meter it properly. as well, cats do die with age, the precious metals do degrade and exit the exhaust, rendering the cat unable to do its job no matter what you use to try and clean it with.

[@remocres]

driving 30 miles so that's about 1 gallon of fuel so if he got 10 to 1 so its not 1 gallon of thinner through it needs 300 miles its unclear about how many miles her ran the way hes talking

[@AaronCross760]

i just switched to premium gas instead of regular and it seems to do the trick

[@kristopherhasenbuhler5393]

Thanks for posting

[@tiggzzgaming2249]

Cataclean is the only one of the fuel additives that works worth of crap. Lacquer thinner won't help unless you take the cats off and clean them directly with it.

[@eyyymanuel]

Just check voltage on rear o2 if stuck at same volt then it's broken change the o2 at the back of cat your reader should show you

[@82_KID]

I haven't seen the GALLONS there in some time. Only quarts. I will look again.

[@kelsycunningham8452]

I'd run a quart of lacquer thinner down the carburetor of old Dodges back in the 70's. It would blow every bit of carbon out the tailpipe, they'd never run better. But I'd be very concerned that in tank fuel pumps won't survive long soaking in that strong solvent.

[@fredkuhn165]

So now you see how it feels to buy gas in ca for $20😂

[@Arkie407]

Thx for the test and sharing your results!

[@fonz1anddone713]

The system needs to run thru X amount of cycles to clear a code itself. Just cause you cleared it and it came back means nothing. Plus it may not even be the cats. Check the O2 voltages up and downstream easy to tell if that was the problem in first place first..

[@Broman-es4sx]

You thinned it out too much run that shit potent

[@joshvaandrew6541]

I tried this on my 2016 Ford Focus. Seemingly running less rough but the code has not cleared

[@MarkHorn-td9mh]

Did u clear the code with a scanner? Otherwise it will still be on.

[@toob247]

Cleaned your fuel injectors and the back of your valves. Not the cat

[@six4standingtall]

177 Miles from a tank of gas ?

[@rwid71663]

not sure where you got the ten to one scotty just said a gallon to a half tank and then take a long trip at high rpm

[@atomicdmt8763]

gotta run it awhile!

[@chrisrhoads8256]

Use 5 to 6 gallons / u have keep useing it / one time doesn't do it you have keep on it 🤛👊🤜

[@SMychal25]

Not a myth, it works and you need to drive at least 150 at freeway speeds or run it at 2500 RPM's for 30 min.

[@jeffnoble9757]

Use one gallon in a half a tank of gas and drive over one hundred miles

[@randallsmerna384]

20 miles? You need to drive like 200 miles! Also, you remove the cleaning attributes of the lacquer thinner through the combustion process. Better to remove/soak Cat in a Lacquer thinner/soap & water mixture.

[@toob247]

Drill a hole in the ca and fill it up and maybe it will clean it like a parts wash. Not doing crap after being burned.

[@user-dh9iy7ty3y]

Clear the code and drive more. I got to 220miles before the code come back

[@sak1320]

Works for me.. 2000 honda odyssey 260000 miles😊

[@sayleebocook6293]

When you do it that way you're supposed to drive at 150 MI

[@xpisporshotx]

That car only have a 10gal tank cause you was running on full. Plus, you're supposed to run at a higher RPM. Like around 2500 rpm for half an hour.

[@jr5324]

I've tried this too but on a 03 jaguar. Didn't work.

[@HS-sr9ww]

probably your ratio is wrong or you don't run on motorway for more than 400miles.

[@WoWgen123]

Could have bought a $2 O2 extender 😂

[@HM-ke1qm]

Where?

[@WoWgen123]

@@HM-ke1qm Any autoparts store or amazon

[@bobbyrobinson5862]

Much luv❤

[@brarautorepairs]

I thought Toyotas made reliable cars

[@jameswhitener123]

The only thing I know cleans catalytic converter to take them off or knock them out Fargo to Philadelphia let somebody steal it

[@5jjt]

Try cataclean. May need a few treatments. Worked fir me. Try the bigger bittle drom walazon.

[@FastInDrift]

Put a spark plug fouler on the rear oxygen sensor and it will work

[@therealjpoe23]

@ $7 its much cheaper too

[@FastInDrift]

You’ll just have to drill out the hole so it’s bigger

[@do5e]

i don't think you did the proper ratio, it's supposed to be one gallon of lacquer for one half tank of fuel. it seems you added a gallon and then filled up the tank, that would have diluted the lacquer too much.

[@AKULA689]

The ratio is 10 gallons fuel to 1 gallon paint thinner! Depending on mid or full size vehicles a half Tank would be approximately 10 gallons!!!!!

[@weskirkland5850]

proper ratio? half tank of gas? What size tank? 13 gallons or 36 gallons?

[@weskirkland5850]

big discrepancy there. ecoboxes have 12-13 gallons. normal cars 15-17 gallons. trucks 18-36 gallons.

[@nothingtodo58]

I suspect it works best on cats that are just starting to go bad.

[@frankthewrench340]

Scotty Kilmer uses soapy water and lets it soak overnight

[@nonspecifie4351]

Cleaned my converter, ruined my engine...

[@robertlennie7466]

Get the adapter that pulls the downstream O2 sensor mostly out of the exhaust stream - problem solved for 20 bucks!

[@santandrjp]

they’re called a spark plug non-fouler, made by Dorman, you’ll need to know the size/thread pitch of your secondary O2 sensor, some applications (my Honda for example) need two (stacked on top of each other)

[@coreturkoane5570]

​@@santandrjpwhat size would fit a 2014 Honda Civic?

[@Stanbott]

You have to drive more than 30 mi for the test

[@mayotrapz9355]

Maybe if you werent always on E you wouldnt be sucking up air in the fuel pump💀

[@CbrF4i600cc]

Crc pass emissions guarentee is what your looking for

[@pigswillbepigs]

Take the cat off and use the chemicals then.

[@queensavage8247]

It does work i just did it yesterday on my 2009 dodge caliber u needa drive 150 miles

[@tosinkiladejo7269]

150 miles of driving can only be achieved if driving to heaven😂

[@frederickpauly2586]

Suppose to be a gallon of lacquer thinner to half a tank of gas

[@nickpad8922]

O2 sensor please don’t put that in your car

[@alejandroaguilar9038]

1 GALLON OF THE ORIGINAL LAQUERTHINNER PER 10 GALLONS GAS. DRIVE FOR 100 MILES

[@rwid71663]

30 miles? it takes a lot more than 30 miles you run it at close to 2500 rpms or at least 2000 till almost gone then refill your tank

[@joeevans644]

It worked for me on an older Tercel. Wondering about a 2014 Chevy if it’s safe

[@polloloci21]

Dude! You only got 177 miles in 10 gallons?!! Is that a 1.8 or 2.4- but either way- that’s bad.

[@tallthinwavy3]

Drive more than 30 miles.

[@tsmith3286]

You mixed it too thin. Go between 1/4 to 1/2 depending on the size of your tank.