Marvel Mystery Oil

[nknowland]

Looking for boaters who have used Marvel Mystery Oil in their marine diesel engine.

When buying a new oil gauge, the mechanic suggested that before my next oil change, I should replace one Qt of oil with one Qt of Marvel Mystery Oil, then run the engine up to temp, and then change the oil. He said the MMO would clean sludge from narrow passages in engine.

Thoughts?????

[leftbrainstuff]

I've seen many supposed 'miracle' products over the years. I worked on many motorsport and oil research and development programs since the 80s. Without exception they are bs.

There are some friction reducing products that have benefits in very high performance applications but are not measurable in normal use. Particularly with a low revving marine diesel. Some major truck fleets run robust test programs which are of interest.

You have two options in choice of engine oils. Synthetics and non synthetics.

For older engines avoid synthetics. They were developed to meet emissions regulations and suit newer engines which have been designed to work well with them. They are not performance products they are emission reducing products which are incompatible with some older seals and piston ring / bore crosshatch patterns. Although they are often marketed with performance benefits.

What do I use in my 34 year old Perkins 4-236? Non synthetic multigrade oil. I change oil and filters regularly. Typically between 50 and 100 hours of engine running time. We also run a preoiler for a minute before starting. This builds oil pressure before starting.

The oil is clean and slowly becomes darker over time. Before it's black change it. The oil captures carbon particles which are responsible for wear. If the oil is black immediately after an oil change then keep changing it until its clear.

The way you clean sludge from an engine is twofold. Firstly never let it get to that condition through frequent oil changes. Secondly only use normal multigrade non synthetic and change it frequently to clean the engine. Don't use flushing oils or 'magic' oils. You don't want to dislodge too much crud too quickly. It will just block oil galleries and increase wear.

The same principles apply to hydraulic steering, rams and transmissions. There is no combustion so the interval between oil changes is extended.

So avoid the snake oil recommendations. They never come with any scientifically robust validation. Change regularly and run a preoiler.

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[nknowland]

Thanks for sharing such a detailed reply. Oil is changed every 100hs with a non-synthetic, multi-grade, and there's never been any sign of sludge or dirty oil.

[dave948]

It's been around since the 20's, my grandfather swore it was nothing but automatic transmission fluid and kerosene.

I've used it very successful to free up stuck motors and as a fogging, storage oil for top ends of engines. I also know people that add it to fuel and swear by it.

I have no experience adding it to engine oil but would have to go with no need to if you don't have a specific problem your trying to correct.

[rockDAWG]

Most of the mechanics I have encountered in the last 40 years do not qualify to make this type of recommendation. No I don't believe in snake oils sold in the auto parts store. They all .are aiming for the uneducated consumers

[Orion Jim]

This is not snake oil. It's been in use for 90 plus years. It was a cheap way of freeing a stuck valve or quieting a noisy one in the older engines. The improvements in modern engines and the use of synthetic oils has limited it value in recent years. Those who still appreciate vintage machinery still find this product valuable. Am I going to use it in my Grand Sport Vette? No. Would I use it in my Ford Flathead? Yup.

[rockDAWG]

Originally Posted by Orion Jim

It was a cheap way of freeing a stuck valve or quieting a noisy one in the older engines.

Well, it is not a new snake oil, but a 90 yo snake oil. It is nothing mystery about it.

It is unproven claim and just a placebo effect that buyer would love to believe. Just like they say. If you build it, they will come. If you make it, they will buy it.

[HopCar]

I agree with Orion Jim, it once was a useful tool to address specific problems in engines. Not so much for more modern engines with modern oils.

It is a terrific honing oil to use when you're sharpening your pocket knife.

[captjcook]

I have no knowledge of using it in oil...I have a 1995 F-350 Diesel that had a miss, best guess injector...occasionally I run Lucas Seafoam in the fuel...tried that, still had the miss...an old school Diesel mechanic (read farm equipment) at the local breakfast joint suggested some Marvel Mystery Oil in the fuel...why not? Figured it couldn't hurt...Cleared it up in a few miles...


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[ggray]

It smells real good.

[cards26]

According to an NTSB post aircraft accident investigation published in 2003, a Marvel Mystery Oil sample tested was composed of 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard.

[GordMay]

Originally Posted by cards26

According to an NTSB post aircraft accident investigation published in 2003, a Marvel Mystery Oil sample tested was composed of 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard.

Indeed.
NTSB Identification: NYC02LA181 ➥ NYC02LA181: Full Narrative

According to the company's safety data sheet:
Petroleum Distillates (Hydrotreated Heavy Naphthenic) also known as mineral oil 60-100%
Petroleum Distillates (Stoddard Solvent) also known as white spirit 10-30%
Tricresyl phosphate 0.1-1.0%
Ortho Dichlorobenzene 0.1-1.0%
Para Dichlorobenzene <0.1%
MSDS ➥ https://www.turtlewax.com/docs/defau...50094-0315-sds

[a64pilot]

I've seen more than once, large Radial Aircraft engines that will stick exhaust valves without MMO.
Old Aircraft engines almost all used Marvel carburators, and this oil was developed back in the day to help keep deposits out of the carbs, it does have a cleaning effect, almopst certainly due to the Stoddards Solvent, which is Mineral Spirits
::Marvel Mystery Oil::.

Read that NTSB report, engine is question had compression's as low as 5 over 80, I'm surprised it would even start much less make enough power to fly

I cut this from a Lycoming SB
b. If the pressure reading for all cylinders is equal and above 70 psi; the engine is satisfactory; less then
65 psi indicates wear has occurred and subsequent compression checks should be made at 100 hour intervals
to determine rate and amount of wear. If the pressure reading is below 60 psi or if the wear rate increases
rapidly, as indicated by appreciable decrease in cylinder pressure, removal and overhaul of the cylinders
should be considered

[a64pilot]

In short MMO will help flush out junk, because it has so much solvent in it, Mineral Spirits.
Auto transmission oil will also, but for a different reason, transmission fluid id essentially 20W oil, but with a very high detergent package, and here it's the detergent that cleans.

Neither of these are very good at lubricating, in fact I'm sure they significantly reduce the oil lubricating properties by if nothing else lowering it's viscosity, so I would n't run it long term, but see no harm myself in using it as a flush, many people put a qt in and run engine until warmed up, then drain and change oil.
Course if you change oil frequently, there is never any sludge to have to flush out.

[uncle stinkybob]

But that engine tune in a bottle.....now that stuff is amazing!!!!