Will lacquer thinner clean a catalytic converter? We test Scotty Kilmer's hack.

I bought a 2004 GMC Yukon Denali with 2 codes. P0420 and P0430. Catalytic converter prices are at an all time high. I decided to try and clean the catalytic converters with lacquer thinner, after seeing a video by Scotty Kilmer.
Scotty Kilmer claims that a gallon of lacquer thinner added to 9-10 gallons of fresh gas, and then driven at 2,000 rpms till the tank is empty has a good chance of cleaning lightly clogged or cats that are not functioning fully. I don't understand the chemistry behind it, but there are several people who have tried it with success. To replace the cats on my GMC would have been more than $1,200.
During my repair of the Yukon, TOPDON offered to send me a code scanner to help me diagnose the issues I was having. They offered a discount code for my viewers as well. If want to try the code scanner that I use in this video here.
amzn.to/3wB8F2k

[@john4x4drone]

I was getting a P0430 code, I did a temp test on my cats, hotter on the engine side by 100F, could not pass California smog. I did 1 gallon liquor thinner in a half tank. Passed smog today. 2015 F150 v6 3.5 TT ecoboost. 100% worked for me.

[@FMJeeping]

Good deal man. Glad it worked for you.

[@crookedreality]

I'm in CA too. Where did you get the lacquer thinner? I can't find anything but the CA-compliant stuff.

[@john4x4drone]

@@crookedreality I just got mine at Home Depot. The light code came back but there was a long enough time in-between my using this technique and getting enough miles on the truck for the computer to do all it's tests. I have since removed my cat and soaked it in dawn and laundry detergent for 24hrs and reinstalled, haven't driven it enough to know if it worked 100% yet but so far so good.

[@chef_papi_pedro2912]

@@john4x4drone how’s it holding up so far?

[@john4x4drone]

@@chef_papi_pedro2912 it came back after a few hundred miles but bought me plenty of time to smog it in California. I also took off the cat and soaked it for 24hr in detergent and it came back in a couple hundred miles. Will replace the cats but bought me time to get the title transferred.

[@edgarhuiltron2184]

Had P0420 code and went to the mechanic. He said I needed a new catalytic converter. I said "no I don't" and came back home to troubleshoot myself. I changed both 02 sensors, Sparkplugs. Check Engine light still coming back on after clearing it almost immediately. I noticed a little oil in the tubes when I changed the sparkplugs, so I changed the boots, Still have check engine light. valve cover gaskets where next. After letting the silicone placed in the joints cure I took my car for a drive this morning for about 3 hours. About a minute before pulling up to my driveway the check engine light went off. :) true story and I feel so proud of myself for saving 2k to the rip off mechanic. note. I took Auto class in high school 2 years, God bless Mr. Schmidt. I am sharing this story because I was about to try the lacquer thinner but I said "what the heck?" Ill just change the valve cover gasket since its pretty simple and fairly inexpensive when doing it yourself.

[@TheWilferch]

Would like to know how changing a valve cover gasket has any bearing on this.... can you explain from a techincal standpoint?...I don't see a connection at all.

[@edgarhuiltron2184]

@@TheWilferch I think it’s because oil was getting into the spark plugs and into the combustion chamber. I haven’t had time to do an update but after a few days it came back on. I did the lawyer thinner and it has stayed off so far. When I removed the spark plugs after sucking out all the oil. There was oil all over the threads. So burning oil was going down into the catalytic converter. My car almost has 200k miles. Everything I did is basically part of a needed tune up after this kind of mileage. I waited almost a year to take care of it. I think if I had done all as soon as the check engine light came on it would have taken care of the problem.

[@TheWilferch]

@@edgarhuiltron2184 ... OK...I fully understand bad piston rings or bad valve guide seals will admit oil into the combustion chamber...and therefore cause oil to be burned, etc. But bad valve cover gaskets will only control the oil to be kept inside the engine....and not leak out.....but that oil in that area sits outside of the combustion chamber.....typically it's oil to the overhead cams and such that have NO WAY to get into the combustion chamber. The combustion chamber will have 150 psi of pressure or more and the oil that sits within the oil galleys that lube the cams is essentially not at any pressure at all.....no way can it get into the combustion chamber and no way it can get processed in the burn process.....doesn't make any technical sense at all. In my view.....putting in a new valve cover gasket is a total placebo..... no affect. Just angling for clarity and not trying to be a jerk.....if anyone else wants to comment here.....no matter which way the comment goes.....I'm all ears. Thanks for understanding.

[@edgarhuiltron2184]

@@TheWilferch well with the spark plug seals are changes with the valve cover gasket. Idk but my check engine lite went off for a few days. Oils in the spark plugs causes problems because it doesn’t belong there. I’m no expert just saying what worked for me

[@slacker_DIY]

​@@edgarhuiltron2184Yes, on some Hondas the valve seals come with a valve cover gasket job. Most other cars don't have this detail.

[@TanManFixes]

it works many times. It worked in my 5.7L . half tank of gas, added 1 gallon LT, drove it 150 miles, and the light went off.

[@FMJeeping]

Good to hear!!!

[@sitbone3]

I used a gallon of lacquer thinner in my tank and ran it for 100 miles. Check engine light stayed on so I manually reset it. A day later it came back on. A week later I bought a can of Dura Lube and ran it in half a tank of gas for 50 miles. Check engine light went out after this. Lacquer thinner didn't work for me at all, but the Dura Lube worked quickly.

[@FMJeeping]

Good to know . Sorry the initial procedure didnt work.

[@user-bj2gq4pt3j]

Maybe a combination

[@TanManFixes]

The LT and the dura lube are the same chemicals. you have to drive more like 150-300 miles for the LT to work. sometimes longer. That said, I know dura lube works as well. All of these products contain mainly acetone, toulene and methanol. These chemicals cleans the injectors, fuel system, fuel pump, CATs, engine, everything. One quart of LT every few months will keep everything exceptionally clean.

[@FMJeeping]

@@TanManFixes awesome info! Thanks

[@2bnax]

THE THINNER MAY HAVE DONE "NEARLY" A COMPLETE CLEANING, AN ADDITIONAL AMOUNT OF THE SAME MIGHT HAVE TAKEN CARE OF THE LIGHT

[@charliemontoya1128]

Tried it in my 2003 tahoe worked like a charm ! Saved me alot of $$$

[@FMJeeping]

Awesome!!

[@stevevash4772]

Remember that if this doesn’t work there is another method in Scotty’s video to try. You remove the cats and wash them in laundry detergent and water, I’d use Tide and the regular one, no softener or other stuff.

[@Goodshaft]

Do you use dryer sheets or a Shammy to dry it off ?

[@anthonyiocca5683]

Cleaning a old disintegrated cat won’t change it condition. I had the same problem on my duel exhaust. One cat cleaned up and passed within 5-10 miles of lacquer thinner in the gas. My other would not pass after many attempts of cleaning while attached to the car. After I removed it to gain that empirical knowledge, I discovered the internal material had disintegrated. So I replaced both of my cats 3 years ago. A few days ago I did a scan of my O2 censors and they was not preforming as they did when I first put them on. So 1 gallon of lacquer thinner in a quarter tank of gas cleaned both very well. My scan of the O2s shown great results. I didn’t wait until a 420 failure, I do the lacquer thinner in the gas cleaning every 15,000-20,000 miles now. With my scanner attached so I seen it produce results in about 10 miles at 65mph with overdrive off.

[@FMJeeping]

Awesome feedback. Nice way to get ahead of the issue.

[@anthonyiocca5683]

@@FMJeeping it’s called preventative maintenance, it’s a sin to wait until the idiot light comes on. Keeping the cats clean will also guard against overheating. The diesel manufacturers engineered a injector that sprays a cleansing fluid directly into the cats while in operation. Gasoline engines need something very similar. Until then 1 gallon every so often is advantages…

[@FMJeeping]

@@shawdoKnights great tip! Thanks

[@joinusmorelikely5428]

You can repeat the process and also with fresh rubber glove clean the o2 sensors tip with brake cleaner and or clean with Emory cloth or mild sandpaper

[@Moshishak1]

Thank you very much for sharing the try. You are right about the extra smooth run right after adding the thinner. I felt the same way in my 4 cylinder sedan. I am still expermenting the try. I did the 150 mile through going to 40 miles closer to my home and back and fourth. I reset the code and I am waithing for it to come back. Then I should drive another 150 miles on regulare fuel without the thinner to see if I will get rid off the check engine light for good or not. This Check Light came from a misfire issue when I drove the car for many many miles without knowing I had th issue.

[@FMJeeping]

The misfire could also be injector related. In which the lacquer thinner might help as well. Good luck 🤞

[@nevaordinary9306]

I appreciate the update to the update. Most ppl would not have came back nor updated and said anything. I just hope ppl actually watch the ENTIRE video but thanks once again. New sub!

[@thisguy7120]

Great work Mark.. Thanks 👍👍👍👍

[@TheBeardedJeeper]

Seems like an awesome hack. I might have to give it a try at some point

[@FMJeeping]

Seemed to have worked. No cat related check engine light anymore

[@gannonfamily2000]

More than one treatment to see if it is savable or not. Also it cleans your intake and frees up the rings if they also were carboned up from allowing bad combustion. A well maintained combustion keeps cats happy. Until they start to disintegrate from age...

[@FMJeeping]

Great info. Thank you

[@joinusmorelikely5428]

I did the lacquer cleaner twice, cataclean and sea foam cleaned the existing o2 sensors( Cathryn had carbon buildup on them and did some other things) with Emory cloth and brake cleaner and the light didn’t come back for about 8 months. Also when using 89 it was fine… but starting to use 87 gas again the service light came back

[@FMJeeping]

Good to know. I've put a few hundred miles on my vehicle and so far there hasn't been an issue. I did swap out my driver's side cat with a new one, but it was a low end unit. Im hoping to get a few years out of it.

[@Sir-Kay]

Made the same video couple of months back, It worked.

[@jeffs4760]

Thanks for the video. I have seen this and I'm hesitant but almost desperate now. I bought a 2010 Porsche Cayenne GTS for a great deal but it had 200k miles on it. Everything works and it runs awesome! (4.8 liter V8) But.....lo and behold it is known for burning a little oil and I have codes P0421 and P0431. I didn't discover this because there was NO CEL when I took it to get the emissions done! It failed. Guess what I learned? The damn CEL light does not illuminate so I didn't know it was throwing a code(s). (burnt light bulb or...) Bought a scan tool finally and have been trying to get it hot and clear with the Italian tuneup. I was going to put some gumout fuel system and injector cleaner in anyway but it seems I needed it for this too. Then I tried CRC Cat cleaner. Didn't work. I'm not getting O2 sensor codes just the Cats. I'm getting ready to pull the trigger on the LT trick because I'm not paying $4000 or so for cats. I did buy the Liqui Moly Cat system cleaner but the LT trick would be easier than spraying in the intake and fingers crossed again. My temporary permit is going to be up in 2 weeks and then I can get one more for a month after that 2nd one. Fingers crossed. I hope this doesn't hurt the system.

[@FMJeeping]

Very similar situation as I was in. The LT trick worked for one side , but not the other. The vehicle idles better and revs smoother. I would do it again.

[@beingsneaky]

Hmm yeah sounds like some removed cel bulb. Hmmm??

[@martincraig2013]

I did this last week to my miata. It didn't work, although I also had the placebo effect where the car ran better on lacquer thinner. I also have the po300. When cold, I have about a 50% chance that it will start with or without a misfire. When it does start with a misfire, it sounds like a rattle can in the exhaust, which too me, means my cat disintegrated. That all being said, I don't think lacquer thinner harms anything. I see it as fuel system cleaner that is probably better and cheaper than anything at the auto part store.

[@e-zward9019]

I wish my kid was that well behaved.

[@FMJeeping]

It was a rare day for them. Lol

[@Masteradamant]

I’m surprised the brown label had an effect at all actually; I learned something. The orange label for sprayers works better. A fuel cap was my issue also 😂 but only because I bought an after market locking cap.

[@FMJeeping]

I didn't know there was a difference. Thanks for the heads up

[@Masteradamant]

@@FMJeeping It’s illegal to buy in California so I got lucky getting it.

[@Masteradamant]

@@FMJeeping Lacquer thinner will damage gaskets if abused too much I read so keep it mind that a new engine is still 3000-4000 dollars

[@FMJeeping]

@@Masteradamant damn. California is rough

[@Masteradamant]

@@FMJeeping There’s a way to turn brown label into orange label 😎kzbin.info/www/bejne/eHbIg4F4nJeGrqM&si=EnSIkaIECMiOmarE

[@michaelangelos5117]

I'm going to try it. 97 Jeep Grand Cherokee Laredo 5.2 l V8 4x4 love my car.

[@FMJeeping]

Hopefully it works for you. Good luck

[@alankelley2676]

Ct here too, watered down fuel these days and emission tests are a joke . Just another tax, was up to 20 year old car, now is 25 years. $20 a car x 2.5 average tests x X amount of cars , CT can’t even pay out winning lottery tix. Scammers throughout

[@FMJeeping]

Yeah CT is not an easy state to live in. Good luck on your test man.

[@robertshurman4455]

thank you for the video do you have a follow up video for this

[@FMJeeping]

Not yet, but everything is still running fine. I can look into doing a follow up . I was thinking about doing it on my Ford explorer as well to help clean it out.

[@kylepalooza357]

I maintain several Ford's. We started getting misfire codes before the cat codes popped up . Fixed the cats and the misfires went away

[@josephberry105]

Did Your Car Sound As It Wanted To Shut Off After Starting It Up And Driving For A Few? Mines Will Start Up After Running For A While It Sound As It Wanna Shut Off And Won’t Go Past 5-10mins? All Shops Keep Telling Me Its My Catalytic Converter And To Repair It’s $2100 I’m Not Tryna Pay That Much Or Do You Think It May Just Be My 02 Sensors?

[@JRW-BJJ]

You have the lacquer can upside down. Turn it so the opening is at the top to prevent the splashing ie let air in. Cheers.

[@dreamer175]

Hey can you clarify what you meant about the 2 downstream os sensors? Did they break and needed replacement afterwards or did they go back to normal after more driving. Thx

[@FMJeeping]

The 2 downstream sensors needed to get replaced after the LT was put into the tank.

[@doug3805]

I have seen way more positives on the LT than negatives. Actually yours is the first. I have used Lucas fuel system cleaner in my 2010 Ford Flex and it really made a difference as far as running but it wasn’t throwing any codes. Thanks for the video.

[@FMJeeping]

Thank you.

[@ethalmurad9506]

What did the Lucas fuel system cleaner do in terms of catalytic converter? Is P0420 still popping up?

[@mjhammer8121]

My daughter's 2015 Honda Fit (88,800 mi.) had the CEL come on and it was throwing a P0420 code, so I added one gallon of lacquer thinner to ten gallons of gas and drove the car on the highway at 80mph for about three hours, and that CEL went off. It looks like many people are recommending a 1 to 5 ratio on LT to gas. I'm planning to do the same with my my 2011 Honda Odyssey now that I've deleted the VCM. (12/14/22)

[@FMJeeping]

Good to hear your daughter's car got fixed. Good luck with your odyessy.

[@InfoSecTangSoo]

How's that VCM disable working out for you? I just bought the S-VCM for my '13 Pilot.

[@mjhammer8121]

@@InfoSecTangSoo My S-VCM is doing well. I've noticed the engine runs smoother since it isn't always switching between two different tunes, and it has more power when I need it. Gas mileage is a bit worse but she stopped consuming oil.

[@ulisesquintero1219]

Hi do you fix your odissy?

[@uione2086]

I want to cancel the VCM on my 2012 honda crosstour. How do I do this?​@@mjhammer8121

[@capri8225]

Good video. I had to put catalytic converters on my pickup truck. The muffler shop talked me into going high flows truck runs great. However, my oxygen sensor readings are all over the place. If the trucks running fine. Is there anything I should worry about? Thanks man!

[@FMJeeping]

Your upstream O2 sensor will bounce between .1v and 1v constantly if reading correctly. The reading from the 02 sensors tell the vehicle to trim fuel or to add and it's constantly a back and forth thing that happens in milliseconds.

[@palillo2006]

If it is a OBD2 truck then the high flow cats don't work. A high flow cat is more like a glass pack muffler that really doesn't even clean the exhaust. The downstream O2 sensor is detecting all the dirty exhaust which is why it is giving you bad O2 sensor readings. Only to get fix this is by using a normal cat.

[@eagleeye2952]

Put an extension fitting or spark plug defowler as it is called, on your pipe at the downstream sensor then put your sensor on the extension. It raises the sensor out of the exhaust stream a bit and might fix it. If not your good to go it's just emissions stuff after the cat. Also your high flow cat might not be getting hot enough so you could wrap your pipe with heat shield wrap before the O2 sensor.

[@sp33drr]

Fyi you can probably go get your truck tuned at a race shop for 600 or less and fix it and make more power

[@andujarjalepena4405]

Worked for me, light went off by itself

[@DrHavok1]

That topdon looks to be a pretty nice scanner

[@FMJeeping]

It is very nice. This is their entry level one. I was pretty impressed with how fast it was and the options available for their ground level stuff. I am looking into their 2nd tier stuff currently.

[@JuanMartinez-yk6oo]

Is that the California legal version of Lacquer Thinner? There are 2 versions I see. Lighter brown label and darker label (CA version) like the one I see in the video. Thanks

[@FMJeeping]

Not sure. I'm in CT, so I don't fall under the CA regs

[@JuanMartinez-yk6oo]

@@FMJeeping thanks for the reply !

[@unti419]

Didn't change anything on my 2011 CTS coupe with the 3.6. Bank one 0420 keeps coming back on every few weeks.

[@FMJeeping]

Then the cat might be too far gone. My drivers side had that same issue

[@roaringhook]

I used 2 quarts of Transmission fluid in a full tank of gas instead. Worked better than the lacquer thinner. Trans fluid is great at cleaning carbon. You can also use it as a motor flush!

[@FMJeeping]

I've only heard that being used to free up seized engines. Good to know.

[@roaringhook]

@@FMJeeping. Back in the days it was used for burning in the valves after a valve job. And you can also use it as a penetrating oil to free up seized nuts. A 50-50 mix with acetone. Can't find acetone use nail polish remover with acetone. The acetone eats the rust. While the trans fluid as the lubricant.

[@Moshishak1]

Wow, I have never heard ot this one!?

[@stodgord3329]

@@roaringhook used trans fluid or new fluids?

[@roaringhook]

I used new trans fluid. Ran 4 quarts 2 quarts twice in 2 full tanks. Haven't had anymore engine codes show up for low efficiency catalyst on the converter at all.

[@capri8225]

Hey, I have a question. What was the temperature of the catalytic converters while doing this? Thanks. Good video!

[@FMJeeping]

Good point , I didn't temp the cats at all during the test. The best I could say is that I got them to average running temps for the vehicle.

[@bobceffo]

I bought cataclean, and it did the trick. Btw. catclean is acetone.

[@FMJeeping]

Good deal!!!

[@bobceffo]

@@FMJeeping yes 50 Buck a liter .... I felt differently smart...

[@FMJeeping]

@@bobceffo yeh $50 per liter is a bit expensive.

[@abbieabbie6818]

I have did any test but I get my friend to test but the other night my floor was very hot on the passenger side in the back by sliding door n I'm thinking my cat maybe the problem, I thought it was the ICV. I got that part just not got anyone to put it in. I'm get the test done n find out if the cat is the problem n I'm try this .

[@ericm493]

Well behaved kids. Kudos

[@FMJeeping]

You saw them on a rare day. Lol. Keeping them separated in the bigger vehicle is a big help.

[@abbieabbie6818]

My van start run bad the next day after my brother was being a so n so to me bc I wouldn't give him any money. I think he did something like put something I my gas tank. I have a locking gas cap now . My brother no longer lives with me but I never know if he comes around when I'm home so my lock gas cap he can not do anything to it . I keep it locked also.

[@williamtackett3814]

@FMJeeping what happens if I dont have ti.e to drive 150 miles at a time? Will a little lacquer thinner at a time do the trick?

[@FMJeeping]

Probably not. I was more fearful of having it in my system for a longer period of time.

[@williamtackett3814]

@FMJeeping so it's not a good idea to run for 50 miles a few times on, say, a quart of lacquer thinner ata time?

[@FMJeeping]

@@williamtackett3814 I personally wouldn't do it. I'd run the whole tank dry at the same time

[@bens1019]

Curious your mpgs. Had a 2005 xl and, got 11 at best 8 in town, why I ended up selling it ran great Otherwise

[@FMJeeping]

I am getting 12 ish highway

[@user-ik8fl2xr5t]

Which lacquer thinner would you guys recommend for a 2013 Ford Taurus?

[@FMJeeping]

I used whatever gallon I could get at HD.

[@trini_boi2414]

I got the same code..I'm waiting to hit half of tank of gas and try this..if I have any success I'll get back on here and let you know..

[@FMJeeping]

Thanks ! And good luck

[@ulisesquintero1219]

Works?

[@8eSix]

Emissions testing is such a joke

[@jeffmccrady9456]

great video!! yeah, i just bought a 04 mercury mini van. got good deal, but check engine light on, took it to shop, said both cats bad! uhgg. im willing to try anything to save 800$

[@FMJeeping]

My thoughts exactly

[@JMAX79]

Tried didn’t work for me. Replaced all o2 sensors & spark plugs, still p0420 bank 1 code. Replaced passenger cat, code popped back up 2 months later. Wow… so discouraging. 2011 Durango.

[@FMJeeping]

Sorry . There might be an underlying issue causing the issue.

[@cjlkberry]

Do you think it would be a good idea to use on a car (Lexus) w/ 256,000 miles. Past experience is with seafoam on a different vehicle. Used sew foam and within a couple months maybe weeks started smoking really bad obviously cleaned it a little too good haha

[@FMJeeping]

I can't speak for a Lexus, but it's been about a year since I did this and the truck is running fine. No smoke or anything.

[@cjlkberry]

Going try it this weekend, with a fresh oil change as recommended! Update you soon. Thanks

[@FMJeeping]

@@cjlkberry I did the oil change after the process. But good luck

[@slacker_DIY]

Damm, I just did an oil change right before dumping a gallon of LT in the tank!

[@LOLONO666]

have you tried to remove it and dip it into the lacquer thinner

[@FMJeeping]

I saw that option as well. I did not try that. I don't exactly remember why I chose against it, but I do know about it, and went with this route.

[@charleysturbos7320]

For any interested I'll save you thousands. You can clean cats with pressure washer and also car wash if you don't have pressure wash. Take care of mount flanges. Worked for seven years at least on 19 year old turbo spider car. Also for drive cycles clearing fast. Go 60 on freeway not below 55 and not above 70. Do this for five minutes on freeway. Keep in drive and pull emergency break slowly and pull off freeway to shoulder till stopping but not touching break pedal. If stick just do same. I don't know if clutch effects this process but I'd just let it go without break pedal. Hope this helps some. PS I'd do thinner to clean out system and get better milage too I'd bet. Nobody is testing the milage before and after bet anything it's better.

[@charleysturbos7320]

Meant unbolt or cut off and reflange cats and then you and or people who try stealing it unbolt instead of cut off,haha. No but really you can then take off yearly or every few years and clean crap out in five gallon bucket too see all the carbon. View before and view after into sun and or bright lights to see cat cleaning difference.

[@FMJeeping]

@@charleysturbos7320 I've seen people soak converters and flush them out. I haven't seen anyone using power washers. But to each is own. I wouldn't try the e brake while driving technique. Something about that doesn't feel safe . I would rather take my chances with the lacquer thinner.

[@jsanders9975]

@@FMJeeping Didn't you say the lacquer thinner caused your 02 sensors to fail?

[@FMJeeping]

@@jsanders9975 I believe doing the test did burn up a set. I think they smoked the downstreams iirc

[@jsanders9975]

@@FMJeeping That sucks, was going to try lacquer thinner but I just replaced the downstream sensor.

[@briansutton7764]

Just a heads up, in some cases you need to preform the procedure a second time.

[@FMJeeping]

I think you're right. I ended up buying a new driver's side cat. It was close to doing what it needed to do via the scanner/love data. But I was running out of time to take the chance.

[@briansutton7764]

@@FMJeeping I thought that I would pass it along in the event that someone who needs to know... knows. It's one of those old school things like using ATF instead of 5 minute engine flush. Or back when everything was carbureted spraying several mist of water into the Carburetor with the engine running to steam clean carbon deposits. The Brightside is it still works on small engines. The More You Know! The more you seem to forget. 🙃

[@jen2202]

Neede this , i used a small bottle of sea foam and it did a little but still have my 420 code so might try this now

[@briansutton7764]

@@jen2202 Try it at a 10 to 1 ratio. I gallon of lacquer thinner to 10 gallons of gasoline. If this procedure does not work in the first or the second application then you'll need to resort to removing the catalytic or catalytic converters and submerging them in a 5 gallon bucket of laundry detergent and water over night. That's only in the event that the catalytic converter is seriously clogged. Otherwise this procedure should work. I actually just pulled into Lowe's I will check what the current price of a gallon of lacquer thinner is in Virginia and let you know in a little bit.

[@briansutton7764]

@@jen2202 It is currently $21.98 per gallon. Or if you buy at least 3 it is $19.78 per gallon at Lowe's.

[@jason6325]

I'm going to try this. My 03 Silverado has 433,329 miles on it. About 6 mo augo it started smoking black. Running like crap sucking gas ect.. I've replaced every sensor on the truck. All new injectors and knock sencors. It finally straitened up for about a month after i put all new 02 sencors in it but now it's doing it again. Scan tool sais 02 sencors again. It's smoking black again and running rough. I have always wandered about the cats. Having almost a half a million miles on them and with it running so crappy for so long has probly carboned them up bad. When i pulled the 02s the 1st time they had so much carbon on then it just fell off when i pulled them. The trail pipe has tons of carbon as well. I'm about to try this lacqur method. It has to be clogged cats. Atleast i hope. I'm out of Parts to replace.

[@FMJeeping]

You might have blow by or something else if you are having black smoke. Youre are burning oil. I'm not sure this will help. If it is. It might just be temporary .

[@InfoSecTangSoo]

@@FMJeeping Black smoke is usually an indication of a fuel/air mixture problem. Grey or bluish-tinged smoke is usually an indication of burning oil. To your point, though, the lacquer thinner technique will likely not fix his problem. Maybe worth a try, though?

[@FMJeeping]

@@InfoSecTangSoo if anything,it might clean out your fuel system

[@sp33drr]

Your piston rings are poop

[@ibberman]

How did you do with the Lacquer thinner ? Is it still smoking black? I got the same problem.

[@athena11711]

I poured one gallon of lacquer thinner in to 1/4 of a tank still have the code. Also replaced all 4 oxygen sensors still have a code. Any other ideas before replacing the cat ?

[@FMJeeping]

Wow! If you went through all that then I would say your cat is probably clogged. A test you can run for that is to drive around for about 15-20 minutes and get the car hot. Get a laser thermometer. Test the inlet of the cat and the outlet of the cat. If the inlet is hotter than the outlet then either the stuff on the inside of the cat is bad or you are clogged. That would be another supporting argument that your cat is bad

[@athena11711]

@@FMJeeping I have to get my hands on a laser thermometer. FYI I spent $2k replacing the other cat

[@FMJeeping]

@@athena11711 they can be found for about $20-50 bucks depending on how fancy you want to go. Harbor freight used to have them. Not sure if they do anymore. But you can find them at HD and Lowes as well.

[@athena11711]

@@FMJeeping Thanks I’ll keep you posted.

[@e-zward9019]

Damn right it will

[@FMJeeping]

Yes sir

[@SamuelPernell-uv8ys]

My check engine light doesn't come on but i ran the test and it said i had a clogged converter..... What do i do????

[@FMJeeping]

If you have the emissions testing. You will need to have it replaced. Just do yourself some testing with a laser thermometer. Get the car hot and test the temp going into the car and exiting the cat . If the temp is colder going in than the exit. Your cat is probably ok If temp is hotting going in than exiting . Then the cat is clogged and most likely will need to be replaced.

[@TanManFixes]

was the car tested on the rollers and failed ? If so I would do 1 gallon LT to clean the system. Then new plugs, air filter, 02 sensors, and 91 octane. with all of that you SHOULD pass a roller test. or at least squeak by

[@born2wrench]

You never want to see the O2 numbers being steady . proper 14.1 fuel mixture you want to see O2 volt reading to move up and down. Above .5 to below .5 volt ..on your primary O2's. Now that can be .500 or 5 volt .depending on the manufactor ..Down stream O2's will generally stay above .500 .(above .5 or 500 or even 5.v will he rich anything below will be lean) oh by the way that thinner will destroy your cat.Thinner may washed away some soot but it will cause the platinum , palladuim ,Rhodium and cerium to break down ..After you have removed the thinner and fresh gas in about 500 miles expect to see your down stream cats to fail.

[@FMJeeping]

steady upstream would mean a bad o2 , correct ? You were right about the burning up down stream o2's. I had to replace both downstreams.

[@truthhurts2149]

How exactly does thinner wash away Platinum? A lot of ingredients in thinner are also in fuel treatments already.Are you a mechanic?

[@slacker_DIY]

So if the crud is being burned off the cat, where does that junk go? To the downstream sensor LoL

[@BrianKeithPREPPER]

I may just say screw it and cut mine out, put a piece of straight pipe in it! give the finger to climate change!! lol

[@FMJeeping]

LOL, if I didnt have emissions in CT . I would. I did on my Jeep since it is nearing the emissions cut off and it is no longer registered.

[@markkloster1557]

My plans exactly. We don't have emissions testing in my state. Once my car is tagged I don't ever have to have an inspection again. The only time I have to have a car inspected is if I buy it from another state. 2002 Lexus ES-300 with 200K on it. I am not paying $1500 - $2000 for a new CAT. Fk that! I am going to give the lacquer thinner a go and see what happens. My plan is 1 gallon thinner to about 5 gallons of gas.

[@FMJeeping]

@@markkloster1557 that ratio might be a bit aggressive. Do it at your own risk

[@4dalow650]

@@markkloster1557 How'd it go?

[@Patriot_-xe9qw]

Agreed. Screw the epa and a cat converter. All this crap is nothing but non sense and just another way for the auto industry to generate revenue and the gov to collect tax forcing you to constantly buy new parts and new vehicles. Oh and screw a O2 sensor also.

[@bryantcash9538]

Will it work in a 2009 Honda Pilot?

[@FMJeeping]

The theory should work. It all depends on if your O2 sensor will fit in the defoulers

[@LT1HILLINGHOE]

I just did the lacquer thinner procedure....it did not clear the code.

[@FMJeeping]

It doesn't always clear on its own. You would most likely need to reset the computer.

[@LT1HILLINGHOE]

@@FMJeeping I cleared the code and it came back. I ran the lacquer thinner twice. Light remains on, but, I will do a battery disconnect reset to make sure. P.S. I just changed the fuel filter yesterday and it was full of dark gray gasoline. The lacquer thinner must have cleaned the fuel tank.

[@FMJeeping]

@@LT1HILLINGHOE your cat may not be able to be saved.

[@LT1HILLINGHOE]

@@FMJeeping That's why I'm installing the oxygen sensor extenders to get rid of the light. Good or bad it's gonna continue to be ran. Car runs excellent other than that code.

[@cooleyhall4103]

will this work with my Ford 2008 E350 Ext 5.4lt passsenger van

[@FMJeeping]

It could. Depends on what's wrong with your car

[@cooleyhall4103]

Was getting the PO430 code for bank 2 catalyst converter below efficiency threshold now getting the PO420 code bank 1 🤷🏿‍♀️🤦🏾‍♀️

[@FMJeeping]

@@cooleyhall4103 this Should help

[@cooleyhall4103]

Question, will it harm my injectors tho?

[@FMJeeping]

@@cooleyhall4103 it would potentially clean them. I had new injectors in my truck when I did it . Been fine

[@MrWang-tu7nm]

My car lexus rx 2004 with 168K miles. I poured in a gallon of lacquer at 1/4 of the tank. Did not work. I poured in another gallon at 1/2 tank. I drove 500 miles in total. Did not work.

[@FMJeeping]

Sorry to hear that. Your cats might be too far gone or there is something else wrong with your car. Potentially O2 sensors or another issue.

[@craigfulmer5069]

If the thinner is burned in engine how is it cleanning the catalist?

[@FMJeeping]

That is a good question. Unfortunately, I don't know the specifics. My hunch is that the lacquer thinner puts off a chemical once burned that reacts with the material in the cat. But that is strictly my guess.

[@alexl9334]

I'm assuming Excess lacquer thinner isnt burned off so the car dumps it in the cat and the excess cleaner eats at the clogged out carbon

[@FMJeeping]

@@alexl9334 I wish I knew the exact process. I want to say the burned off thinner reacts with the carbon and loosens it up.

[@alexl9334]

@@FMJeeping yeah cause I'm thinking since the excess fuel that isnt burnt is sent out the pipe like two step that gas mixed with the thinner would make it like that

[@BLKCFII]

So, you mean lacquer does not hurt a car's engine? 2015 Regal 4 cyl 2.4L? By the way, Scotty did not say drive at 2,000 for an hour and a half. He said, either drive for an hour and a half OR run the engine at 2,000 rpm in the place of driving an hour and a half.

[@FMJeeping]

I like keeping the rpms up to keep the flow of exhaust moving and the temp up as well.

[@privilegecarter]

Will it work in 2003 clk 500?

[@FMJeeping]

Not sure. I only tried it on my Denali so far

[@just_a10]

Where can you buy it at

[@FMJeeping]

I got mine at a Home Depot

[@josephinegonzales-rosas8653]

Why are the numbers moving and blinking

[@FMJeeping]

The camera doesn't like the frequency the light emits from the display. I get a similar issue with my led lights in my garage.

[@paullinos820]

Do you need to drive 100 miles in one day or it can be in two three days?

[@FMJeeping]

I would try and do the mileage in one day. That way the cat will stay hotter, and longer. Or at least that is my belief.

[@3sgtepwnzr]

If you are to try this hack, you should try to burn off all the thinner in one go. Some of the solvents in the thinner will separate from the fuel if left sitting so you might be driving on a different ratio of chemical to fuel which is no bueno for all the other components in the fuel system. Option A is to change with a new cat assuming you know it’s not some other issues causing the cat to go bad (misfires), option B is to remove the cat and manually clean the media if it’s still salvageable, often times, it may not be, I would put running thinner in your tank as the Hail Mary option. Good luck.

[@isaiahboothe4299]

Does this work with diesel engines?

[@FMJeeping]

I am not sure. Sorry

[@isaiahboothe4299]

@@FMJeeping no worries. Thanks for responding

[@pdavis4436]

How's it running now?

[@FMJeeping]

Runs fine. Just took two 400 mile trips with a fully loaded trailer. Runs and drives great.

[@pdavis4436]

Thank you. I'm thinking about doing it to my Altima code just came up but I'm not having any issues with driving. Has 140k on it. I put 2 bottles of Chevron/tech fuel cleaner like 3 weeks ago I wonder if the cleaner could've caused build up on the converter

[@FMJeeping]

@@pdavis4436 hard to tell. Unless your engine was really carboned and it knocked a bunch of junk loose. This was the option I tried . $30 attempt to save $1400 . Do at your own risk, but I feel like it helped one cat.

[@adonis2116]

@@pdavis4436 I've been able to get an extra year or two out of my 3.5L Altima using Cataclean, but I think now it's time for lacquer thinner.

[@MustangGuru]

It’s like when you put your oven in self clean mode.

[@FMJeeping]

I think you're correct

[@ahmadnjidda6207]

Hi. can I use any Lacquer cleaner?

[@FMJeeping]

I think so. I used the brand that was available to me from home Depot

[@ahmadnjidda6207]

@@FMJeeping Thank you

[@thomasgoyen9324]

The biggest issue is if you used the south coast lacquer thinner it may not work as good

[@FMJeeping]

I didn't know there was a difference.

[@brandonknight7240]

Why not just buy mass air flo sensor cleaner and take out the o2 sensors and clean them as well as the maf

[@FMJeeping]

I did try this first No change to the read out. Which is why i went onto the lacquer thinner,.

[@brandonknight7240]

@@FMJeeping mine run like garbage. I tried cleaning with aerosol no change had 2 buy a new MAF sensor- rock auto then it ran great but a huge noticeable difference in using more gas im like wtf i cant win either way

[@crazee6821]

The Chevy 4l60e transmission will fail if you drive it with a misfire! It happened to me several times

[@FMJeeping]

That makes sense on why it failed

[@palillo2006]

Ya, a misfired damaged cats will not get better using this method. They get damaged by melting the honeycomb structure inside. Using this method is more to clean the cats if you are burning oil and there is a buildup.

[@FMJeeping]

It was only speculation the cat was mis fired damaged. I took a shot. I was able to recoup the passenger side one, but had to replace the driver's side. So it wasn't a total waste.

[@brandonknight7240]

If u had a tub to submerge the whole cat and vibrate the fluid ( laquer thiner) that might work

[@FMJeeping]

@@brandonknight7240 that could work. Scotty suggested something similar as an alternative

[@jdh6870]

I see nobody asked the important question, what did you get a Dunkin?

[@FMJeeping]

Hot coffee . Med , almond milk, 1 shot of caramel

[@jdh6870]

@@FMJeeping I have a chevy cruze with a 14 gallon tank. do you think a quart of LT with half a tank of gas would be sufficient?

[@nevaordinary9306]

@@jdh6870no 1 gallon to half a tank

[@andyp3213]

This DID NOT work for me my cat might have been gone to far BUT my spark plugs looked bad after I tried this.

[@abbieabbie6818]

2000 Chevy Astro van

[@FMJeeping]

Most likely.

[@CharlesLease-ei1ee]

Yes, the light will go off, but it will throw it in the history. You will have a history code.

[@FMJeeping]

In my state history codes won't fail you. If the readiness codes are satisfied, you will pass. So if the light is off and you have completed the drive cycle. Then you will pass

[@Patriot_-xe9qw]

History code…lol.

[@bobbiinfield6374]

what if you do it one more time

[@FMJeeping]

It probably wouldn't hurt. In hindsight. I probably should have done it one more time

[@robertmitchem6635]

Will it clean 02 sensors ??

[@FMJeeping]

Im not sure. The process is more for the catalytic converter. It might help loosen carbon on the sensor. But I can't be sure

[@SimonBarsinister]

Tried it didn't do a damn thing. 2010 buick with 3.0l.

[@FMJeeping]

Sorry man. It might not help everyone.

[@derekkchung]

Explain the science to an idiot like me. Any chemist here? Wouldn't lacquer thinner be totally burned up during the combustion and turn into hydrocarbon like the gasoline? What additive or active ingredient does it have that can resist the heat and pass down to coat or clean the element inside the catalytic converter, and if so, how does it make it work better?

[@FMJeeping]

I wish I could break it down for you. Only guessing here, but the chemical reaction from the burn off from the lacquer and the carbon in the cat loosens up and eventually blows out the rear. But once again, I am not a scientist, or a chemical engineer. Just an idiot with a camera and a drive to save money

[@slambam6191]

Nothing like making a video while driving around with the kids in an a old vehicle that the dash lights are flaking out in.

[@FMJeeping]

The kids were happy and I have AAA. It worked out in the end .

[@samlegha1861]

So Scotty Kilmer is an online reference for mechanical repairs now?? Good luck with that!

[@FMJeeping]

😂😂😂. In some cases. Sure.

[@samlegha1861]

@@FMJeeping I used to respect his opinions and ideas until he turned toward the commercial profiting... 😞

[@FMJeeping]

@@samlegha1861 agreed

[@justayankhouston741]

If you cant fix it this way, they make more or less a threaded sleeve that fits into the O2 sensor threads then you screw the sensor into that. Basically moving the O2 sensors out of the exhaust stream.

[@FMJeeping]

Lol. I made a video about that as well.

[@TurboMountTV]

Basically masking problem not fixing it.

[@FMJeeping]

@@TurboMountTV in my video I did on the mil eliminator , I definitely said It is only temporary , and not a permanent fix.

[@terryslay1]

@@TurboMountTV If it keeps me from having to contribute any more more money to the money grab the government likes to call the Clean Air Act, Im all in!

[@TurboMountTV]

@@terryslay1 Except a catalytic converter is one of the few things that make sense. in 1970 Kalifornia you could barely see across the freeway.

[@Helmuesi911]

$40 for a gallon of lacquer thinner? Where do you live?

[@FMJeeping]

CT

[@TheDevonwurz]

My car was clogged and I had no check engine light for it. One for the maf . And it was so clogged like melted.

[@FMJeeping]

not good , hopefully you were able to get it situated.

[@Yanbrymenocu]

@@FMJeeping I buy 1 gallon of lacquer thinner on Lowes I gonna try if my po420 code on my 2007 Nissan versa hatchback is not showing up anymore.

[@FMJeeping]

@@Yanbrymenocu good luck. Hopefully it works for you.

[@noneyabiznass]

@@Yanbrymenocu did it work

[@Yanbrymenocu]

@@noneyabiznass unfortunately it doesn't work for me the check engine lights come back but I will try on the second time

[@lorenzofiduciagarbuglia4203]

Hi guys, my cat is also signed and to replace it will cost me €1800 'yes I am living in Europe ' ☺️ I see lot's of videos but none of them is talking about what engine.. Those anybody did it with a injection engine?

[@FMJeeping]

My engine is a fuel injection engine. It worked pretty well. I did it on a 6.0 LS engine. Fuel injected.

[@SooSmokie]

is this a joke? all newer cars are fuel injected

[@anavan7]

@@SooSmokie Tesla…😂 j/k

[@SooSmokie]

@@anavan7 😭🤣👌 Totally got me there..lmao!

[@nathanielholloway8267]

I have a Audi 2015 a7 and the p0420 came up.. now I bought a gallon of laquer thinner and drove 9 highway miles at 60/70 mph..and I sat and ran the RPM@ 2500 rpm..for well over 30mins..I hope it works-to🤨

[@FMJeeping]

Good luck!!

[@mistersecret88]

11.07. Looks like newington

[@FMJeeping]

You're not wrong.

[@mistersecret88]

@FMJeeping Ha I knew it! GASMAN.

[@FMJeeping]

@@mistersecret88 yeah . Thats the gasman .lol

[@keepinitr33l]

What's a catalyst converter?

[@FMJeeping]

lol, you are 100% correct. I titled the video incorrectly.

[@gam3kid]

It's what California used to extract unnecessary money out of citizens while they allow people to shit all over the street

[@Jkl306]

😂

[@ThisTimeTheWorld]

It's a jewish fake muffler with little metal grids inside that cost enormous amounts of money compared to normal useful mufflers.

[@timjones3423]

Daddy, are we there yet?

[@FMJeeping]

😂😂😂😂😂

[@PjHipp]

SMH YAK YAK YAK

[@che2335]

U bought American i dont need a scan tool to read that problem. Buy a Tundra and make 2 trips or a mitsubishi fuso panel truck for your business and keep your profits instead of supporting local mechanics.

[@wittyanduniquehandle]

Greatest lie ever told: "The ABS light is something I'm planning on fixing." 7:26

[@FMJeeping]

Lol. I did end up getting it fixed.

[@Jerry-up8bk]

It's NOT a LIE ! IT WORKED for me ! My car was getting 7 miles to the Gallon , 1 Gallon L.T to half tank of gas , DOUBLED my Mileage! .

[@miketran3760]

Lacquer thinner might damage your fuel system and engine, might cause fuel leaks and fire . Fix your car the right way! 🙄

[@FMJeeping]

I did this nearly a year ago and i havent had any issues . I did do an oil change and ran the gas down as low as I couls to refill with fresh clean gas

[@tim88114]

Thanks for the info but maybe try lowering the music volume. Very aggravating while watching a video and all of a sudden your music is blaring away .

[@FMJeeping]

Got it. Thanks for the feedback

[@crashtke]

Sucks about the converter man.

[@FMJeeping]

The torque converter? That was a huge disappointment, but Im over it now. The work has been done to fix it, and the cost wasn't terrible .

[@vacamike]

This video could have been 2 minutes long

[@FMJeeping]

Probably, but this was a video story of what i did, but thanks for watching

[@js6916]

Way too much BS, just tell everyone what your video says

[@FMJeeping]

It worked! Sorry. That would be a short and not a video.