Deisel Fuel in Crankcase Oil

[ron6785]

Has anyone heard that a small amount of Petrochemical Deisel in you crankcase oil has some beneficial cleaning qualities. I've never heard of such a thing. Can any of you chemists out there weigh in on this?? I know in older engines with worn rings you get some deisel in the crankcase because it leaks by the rings

How much would be ok???? good???? bad????

 

[mobilemn1]

It would break down the viscosity of the oil,,,,,,that is why you have real black oil between oil changes on engines that have blow by around the rings. The combustion byproducts that get by are corrosive and over time breaks down the lubrication ability of the oil. The oil gets thin and dirty with soot. Most oil is single refined, some double refined. Some of the oils that we thank are the best in the world are really not. Personally I want oil where the oil is supposed to be and fuel where its supposed to be.

Oh, and not a scientist.....JMHO

 

[Will]

Assuming you're running diesels and using oil meeting the manufactures specs. there is no need to add any cleaning agents. The oil already has high detergent characteristics. Adding diesel fuel in any quantities, only reduces viscosity (a bad thing).
Will

 

[jim rosenthal]

I wouldn't do this. Diesel doesn't have the lubricating qualities that engine oils have, and diesels are tough enough on oils that there are specific diesel-rated oils. Use those, change them at least yearly or every 75-100 hours, and you do right by your engines. Clean oil and lots of it is the best thing for the internals of any engine.

 

[MikeP]

I'd say you don't need any additive for this purpose BUT if you really think you need additional detergents for some reason, use Marvel Mystery Oil. MMO was Mil Spec years ago for this and other purposes. But it is a SERIOUS detergent and sometimes what you DON"T want is something that loosens deposits, etc. Remember that those deposits have to go SOMEWHERE!

 

[ron6785]

I'd say you don't need any additive for this purpose BUT if you really think you need additional detergents for some reason, use Marvel Mystery Oil. MMO was Mil Spec years ago for this and other purposes. But it is a SERIOUS detergent and sometimes what you DON"T want is something that loosens deposits, etc. Remember that those deposits have to go SOMEWHERE!

Yea, this was on a deisel blog and I didn't understand the logic either, unless you where using as a cleaner just before changing oil , however they were talking about using like Marvel as an aditive. I don't use marvel in the oil of my dd's although I use it in the deisel and gas in my vehicles.

 

[Genesis]

I wouldn't even CONSIDER intentionally putting fuel in my crankcase oil. That's just begging for severe bearing damage.

 

[stormchaser]

I'd say you don't need any additive for this purpose BUT if you really think you need additional detergents for some reason, use Marvel Mystery Oil.

Bah, MMO is just Naphtha and mineral spirits, 80/20 mix. Nothing special about that. It really isn't any more detergent than diesel fuel or ATF. But I';ve used it with good success on a gas engine, every good upper end cleaner.

OP, yes, you can use Diesel fuel or MMO, or ATF as a detergent/cleaner. But I wouldn't run it in there all the time. Ad some a few hours before an oil change to allow it to circulate, then do an oil change. This technique works great for old gunked up gas car engines, never tried it on diesel.

 

[Passages]

Dave beat me to the punch on this one.

Back in the olden days (1970's and earlier) it was not uncommon to flush the crankcase of old GASOLINE cars to get the sludge deposits out. Remember, this was before the days when everyone used high detergent motor oil. Did it myself a few times but I used a 50/50 blend of kerosene and clean oil, not diesel. Plus, I would only let the engine run at idle for a few minutes max. Drain out the flush mix, replace filter and oil and you are good for another 60,000 miles.

Don't do this on a diesel or a modern gas engine.

 

[MikeP]

"It really isn't any more detergent than diesel fuel or ATF."

I don't agree. As an obvious example, diesel fuel won't clean the deposits out of your diesel fuel tanks/system; MMO will, with a vengeance....

I was a US Army Tank Battalion maintenance officer for about a year in the early 70's. MMO, at that time at least, had a MilSpec number and was specified for several different applications on gas/diesel engines to remove deposits from fuel systems, crankcases, upper cylinders, etc.

There are a huge number of stories of old siezed-up engines having some MMO poured into each spark plug hole and a couple of days later the engines being started with no other work done and running afterwards for years, again with no other attention. I was personally involved in one of those stories with an old cement mixer that is still running nearly 20 years after the MMO unseized it with nothing else being done since then other than gas and, as the owner says, "oil when it gets low."

 

[67hat34c]

Cant see how you would need to add anything to diesel oil. If you think it is sludged up then pull a valve cover and inspect. Gasket is cheep.

 

[stormchaser]

I somehow think the stuff has changed or was never the same as the Mil spec stuff. Look at the Material Safety Data Sheet... http://www.google.com/url?sa=t&sour...6fW9Dw&usg=AFQjCNE4b-g5CAmfn6DX5wXNXo-zOyuhDg

It's simply Naptha, Spirits, and a tiny bit of WATER. I guess that makes it closer to Kerosene than diesel or ATF? either way, it's simply a light petroleum distillate, with alcohol and water added. But who knows...it DOES seem to work well on old gas engines...

 

[Brian Degulis]

NO MMO NO DIESEL NO KEROSENE There is absouloutly no reason to attempt to flush a diesel unless it's contaminated with water or something like that. These engines run high detergent oil they don't sludge up like gas engines. YOUR ASKING FOR TROUBLE TO ACOMPLISH NOTHING.


Brian