[rocknjeep]

Well I look at it this way. The Jeep was created for the military in 1941. Marvel Mystery Oil was used on everything in the military, jeeps, planes, boats, ships, trucks, amphibious vehicles. My grandfather (an old Navy man) said they used the stuff all the time and still to this day uses it when troubles arise.

Has anyone used it? If so what were your thoughts or findings?

[Talos]

I stopped using it in the crankcase when I switched over to full synthetic oil but I still pour a few ounces into the gas tank every few fill ups. When I first got my Jeep 18 years ago it pinged pretty bad but that was cured after about four tankfulls adding Mystery Oil. Good stuff, in my opinion.

[Brandon_YJ]

Originally Posted by rocknjeep

Well I look at it this way. The Jeep was created for the military in 1941. Marvel Mystery Oil was used on everything in the military, jeeps, planes, boats, ships, trucks, amphibious vehicles. My grandfather (an old Navy man) said they used the stuff all the time and still to this day uses it when troubles arise.

Has anyone used it? If so what were your thoughts or findings?

But your engine was made post 1991, the logic does not compute.
Some people live by it, some think it "can't hurt", and yet others think every mechanic-in-a-can is a mountebank ware.
I've used it in my Jeep. Never noticed an improvement or problem.

[xxxflhrci]

Good ole' Marvel Mystery oil......ATF mixed with kerosene.....Yep, just because granddaddy used it, it's gotta be good. More hype than anything, IMO. The propaganda on the can makes for a good read though and it smells nice.

[pacodelahoya]

I use it to clean my guns. Gets cosmoline of the milsurps and gets carbon off the shooters. It's like a cleaner, lubricant protectant at about a fifth of the price of the big names. None of my guns are rusty, and they all run just fine.

Have never used it in a vehicle.

[rocknjeep]

Just a bump for the morning rounds.

[rustywrangler]

Originally Posted by rocknjeep

Just a bump for the morning rounds.

Don't bother with it. No real gain and some have had issues after using it.

[pat8942]

Grampa used asbestos on the furnace pipes too and we all know how good that stuff is.

Originally Posted by xxxflhrci

Good ole' Marvel Mystery oil......ATF mixed with kerosene.....Yep, just because granddaddy used it, it's gotta be good. More hype than anything, IMO. The propaganda on the can makes for a good read though and it smells nice.

[Talos]

I found this in a Piper Owners forum. Interesting list of ingredients!
I stand by it as a fuel additive but for the crankcase- just run a good full synthetic oil and forget about additives.

[azgurney]

I never used to believe in this stuff either until several years ago when my lifters started ticking. I put in a quart 200 miles before a oil change and the ticking went away and has not returned. I got my $5 worth.

[rocknjeep]

I'm gonna try it out and see I guess.

[SleddinJeeper]

Originally Posted by pat8942

Grampa used asbestos on the furnace pipes too and we all know how good that stuff is.

Are you being sarcastic or serious? Ahaha sorry, couldnt tell if you were saying that the Mystery Oil is good or if its bad. With all the hype of how "bad" asbestos is now a days its hard to tell.

On a side note, why am I the only person whos never heard of this Mystery oil?

[pat8942]

I was just trying to say just because it was used many moons ago doesn't mean it was all that great in the long run.
IMO if you need a little inside engine cleaning it's ok infrequently but, you don't want to start over doing it and cleaning the oil off the cylinder walls and bearing surfaces.
Asbestos was all I could think of at the time.
Oh and BTW there was a little sarcasm intended.

Originally Posted by SleddinJeeper

Are you being sarcastic or serious? Ahaha sorry, couldnt tell if you were saying that the Mystery Oil is good or if its bad. With all the hype of how "bad" asbestos is now a days its hard to tell.

On a side note, why am I the only person whos never heard of this Mystery oil?

[J-Quad]

I have had first hand experience with MMO - although it hasn't been in my Jeep, rather with it in my two Cub Cadet garden tractors.

After adding a few ounces to the crankcase and to the fuel. Within the first tankful of gas they both stopped smoking blue when laboring up a hill or such.

I will continue to use it in my old Cub Cadets. I have put it in my autos but did not notice any differences........ However, because of the success I've had with it in the Cubs, I will try some in my recently-purchased 100+K mile 4-cyl '95 YJ which has a loud 'tick' in it. I was just thinking today that I'll dump some in the crankcase and into the fuel tank and see if it will clear up the 'ticking'.......

As was pointed out earlier, I've read many folks swear by in in air-cooled engine uses, whereas not as many 'believers' for water-cooled engine use.

Just my 2 cents,,,,,Good Luck!
J-Quad

[Castr8r]

I've been useing it in the gas tank for years on everything from weedeaters to Jeeps to trucks to motorcycles. I have used it a time or two in the crankcase when I suspected a sticking lifter (seemed to work). MMO in the mower or weed eater gas will do the same as Stabil, and keep the gas from going bad. I've never tried it for cleaning firearms, but I think I will- it just seems to make sense to me. FWIW- I'd always heard that adding ATF to the crankcase would free up stuck lifters- didn't work for me, but did start useing more oil... MMO did a better job of freeing up the lifters when used several months later, but didn't do anything for the increased oil consumption. Now I use Mobil One exclusively in all 4-stroke engines with no problems; still use a shot of MMO in the tank...