Ever use Marvel Mystery oil? Why?

Z

ZZman

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I have used it in the past but not lately. I used it for the fuel not the oil. My main purpose was to lube the fuel pump, injectors and upper cylinders. I did seem to notice slightly better mpg when using it.

How about you all? Fuel, oil, both?
 
I've run some through a neglected lawn mower that I didn't feel like tearing into. Seemed to help at the time, but I bet Berryman's would have worked better.
 
I use it all the time in the gas of my 65 mustang 200 c.I. 6 cyl. But not my 98 mustang or my 2017 Nissan Frontier. OH, do also use it in every can of gas I buy for my OPE. Have no real evidence that it helps anything, but got started using it when I was farming with 1940s tractors in the late 50s/ early 60s. Never had to do a valve job like the neighbors did. MMO or coincidence? Back in the day when my cars were all ones built before there was unleaded gas, I used it in them also. Have never used it in oil, but might if the circumstances were right.
 
I've used it on engines (two CB750 DOHC) that have sat for a long time to soak the piston rings before manually turning them over, and ran it in these motors to keep the carbs clean. I also use it to clean carbon out of rifle barrels.

I've put some in the crank case of a 3.8 ford pushrod engine to clean it up, that seemed to work. Also used it in the gas tank of a few vehicles not sure if it did anything but it didn't hurt anything either.

It will definitely clean up carbon as I've seen when using on the motorcycle engines and rifles so I would think it will clean the pistons when added to your fuel as a cleaner.
 
It seems that most people either swear by it or hate on it. It does give results on piston soaks for stuck rings. I also had great results over a few months in decarbonizing valves and combustion chambers in a long neglected slant 6. It blew carbon out the tailpipe for a long time until there was no more. That was with mild fuel dosing. Problems with carburetion and ignition had also been sorted. Other products may have done the same for either issue but I can't imagine that they would have been more effective. It's earned fame was on older carbureted cars and simple flathead lawn mowers for valve maintenance.

I have always passed on adding it to the crankcase.
 
I used it in the 80's added to oil before a change. Don't use it anymore. I had an old can i used some for drilling metal, but i'm not sure that was a good choice.
 
Plenty of previous threads on this subject
I suspect many people who chime in and call it snake oil or opine that it has no relevance in modern engines have had no experience ever using it.

It does in fact have a mild solvent and lubricating property to the formula. From a personal example, the fuel gauges on Nissan 370Z's have a known issue of getting wonky at times and not registering full when users have even filled them until the overflow point.
A dose of few ounces of MMO solves the problem for the next few tank fulls at which point another dose is required. Apparently the crummy gas, even top tier can cause issues with the sending unit in the tank and MMO either cleans it with the solvent or lubes it. Whatever the case, it works. I don't know that I would ascribe magical properties to it but it does work in certain applications.

The cost is very moderate and adding 8 oz. to a tank of gas every 3-4 thousand miles seems to be a good PM procedure.
 
gman2304 said:
No. Snake oil.
Click to expand...

Such a kneejerk and overused term here. In fact, it does have solvent/detergency capabilities and is probably useful in certain applications, so it is not "snake oil".

It is however largely obsolete with detergency in fuel and especially Top Tier grade fuels so yes, there is no reason to use it in a modern gas engine. Marvel might be more useful in older vehicle applications for gradual fuel system clean up or when used as a cleaner in power equipment where using expensive FI cleaners like Techron might be overkill...
 
Not a fan of this guy when it comes to motor oil conclusions, but his videos on fuel additives are far more convincing/relevant:

 
Air tool. I forgot about that. I have an oil can that I filled with MMO maybe 20 years ago that I use to put a drop or two from in air tools every so often.
 
I was recently given a 2002 Blazer with 108K miles.
I ran a bottle of Techron in one tank.
Then some MMO just to get that warm and fuzzy feeling.
Now here is the strange part the person I got it from said that when the gas needle hits 1/2 it starts bouncing up and down.
Since running the Techron and MMO the gas needle has not bounced around.
Maybe between the two they cleaned some gunk off the float?
I still dont trust it so I have filled it at around a 1/2 tank and it takes about 10 gallons in an 18 gallon tank and 15 MPG,yuk.
 
The 10% ethanol already in your gas is a better solvent/cleaner than any component in MMO.

In the crankcase, the alcohol and naphtha (the "cleaning" components in MMO) evaporate before the oil reaches operating temp so I don't see how that could do anything except oxidize the oil.

I could see it used to soak pistons/rings in an old engine that's sat for a long time, but I personally use acetone for that.
 
ZZman said:
I have used it in the past but not lately. I used it for the fuel not the oil. My main purpose was to lube the fuel pump, injectors and upper cylinders. I did seem to notice slightly better mpg when using it.

How about you all? Fuel, oil, both?
Click to expand...
Used to add some to the fuel tanks of a couple of old Farmall gasoline engine tractors we had when leaded fuel was discontinued. The general agreement among the farmers and tractor mechanics of that era and locale was that it might help somewhat with the engine valves. At any rate, quite a few people added it to gasoline engine tractors for that reason, whether right or wrong. One thing is for sure, MMO has been around for a long time and people are still buying it.
 
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gman2304 said:
Not knee jerk at all. I’ve thoroughly researched MMO. I, as well as many others have known for decades that the only thing MMO does is lighten one’s wallet.
Click to expand...
Tell that to all the lifter ticking engines, that "magically" stopped ticking after recommended application of MMO. That's just the ones I had experience with, seems like many others had similar experience.
As well as fuel gauges that "magically" started working after MMO.
And carburators that somehow stay clean when MMO is used, but do get gummed up from just fuel being used, or even when fuel+Stabil are used.
Just my experiences, can't speak for others, but mine are enough for me.
 
gman2304 said:
Not knee jerk at all. I’ve thoroughly researched MMO. I, as well as many others have known for decades that the only thing MMO does is lighten one’s wallet.
Click to expand...

Really? Can you tell us what's on the MSDS and what some like a certain Mod who works in the industry here have said about it?

And as far as "lighten the wallet", it was previously $3.88 at Walmart for a 32 oz bottle which lasted several weeks of dosing depending on how much one drove, but I haven't bought it in a year or more. I'm sure many here waste more money driving stupidly than they ever would occasionally using a fuel system cleaner...
 
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