Adding TCW OIL to diesel fuel to enhance Lubricity

[Crew of Turning]

Well, does anyone wish to give me some insight into this approach. I read about some truckers with older diesels that were having dry fuel issues and started adding motor oil to their fuel to uptick the lubricity of the fuel. I confess, without thinking, I started to do this two sailing seasons past with no negative effects but not sure if the results were perfect. The idea was to protect the fuel pump, banjos, and injectors. The volume added was 2 ounces to 5 galllons imperial. The engine (s) are a Yanmar 3gm20 1981 with serial # 000392 and still runs well. The other is an older Yanmar 2qm20 1977. Why two engines? sold a boat and bought a boat. I figured that the TCW oil would burn nicely without ash or soot, so far no snags.

[HappyMdRSailor]

There are threads of cruisers doing this very thing.... Much larger concentrations too...As I recall... No downsides!

[svHannabel]

I don't have any personal experience with TCW oil in diesel fuel (or any other additive for that matter, but this thread indicates other folks seem to be doing it too, particularly for older diesels.

Personally, I'd check with Yanmar and a trusted diesel mechanic.

[Stu Jackson]

Lubricity on the "newer" (like, maybe 5 - 10 years now) has been addressed by the oil ompanies, they add it in before they sell it. You can also get little cans of additives if you're so inclined.

This urban myth keeps coming up over and over again.

Completely unnecessary.

[rockDAWG]

Gimmick. Totally waste money.

But if it makes you feel better, yes why not. Throw your money away. If you throw your money my way, at least I will not label you as a sucker but instead I would say thank you so much.

[Mark1977]

Myth or not , I know all the fishing boats around here put a litre of trans fluid to a tank of diesel. Very common , does it do anything? dunno.....

[Geoff54]

There was a well deigned test done by one of the diesel truck sites a few years ago - google will probably track it down for you but from what I remember:

Opti-Lube XPD was the best additive (I bought some after reading the test)
Motor oil did almost nothing
2 cycle oil gave a reasonable improvement in lubricity (I did wonder if a really good racing type synthetics might have been even better). It was mid pack amongst the additives some of which were worse than plain diesel.

[pistarckle]

Many fish boats will pour their used engine oil in the fuel tank to get rid of used oil . My 6-71 Detroit ran with 48 qts used oil mixed in 450 gals of diesel for many , many years .

[kentobin]

If I remember correctly atf can be used as a degreaser and is one of the ingredients used in homemade penetrating oil. It also allegedly will remove auto paint. I remember people would dump some atf into the crankcase of an auto engine to help clean out the sludge, that was 40+ years ago and it wasn't a new idea then either.

[sailorchic34]

I'll use a few oz of cheap 2 stroke oil, now and then when I add 5 gallons of fuel, based on my own understanding of current diesel formulations. It may help a bit to reduce wear on older diesels, Not required at all on newer diesels.

Adding oil or 2 stroke oil to diesel will not hurt the engine, though it may not help either.

[a64pilot]

ATF is high in detergent and will do a reasonable job of cleaning injectors, as a lubricant, not so good.
ULSD is low in lubricity, adding an additive that is specifically made for that is not a bad idea, two stroke oil sounds good but isn't very effective. It's actually the common rail high pressure Diesels that suffer the most, particularly the injectors. I replaced my injectors in my Duramax Diesel pickup truck last year, about $3,500 in parts.
Common rail Diesels are particularly sensitive to dirty fuel as well, tiny, tiny holes in the injectors subjected to as high as 50,000 PSI, all it takes is a tiny bit of dirt particles to cut the injector nozzles like a water jet. Fuel polishing with as fine as a 2 micron filter may do better for them than anything.

[Geoff54]

Out of curiosity, I went looking for the test that I read and found copies in several locations.

They appear to have used the ASTM International standardized diesel lubricity measurement. Credible? Sounded credible to me and certainly better than the usual recommendations with nothing to back them up. But you be the judge:

http://www.johnfjensen.com/Diesel_**...itive_test.pdf

[psneeld]

Originally Posted by Geoff54

Out of curiosity, I went looking for the test that I read and found copies in several locations.

They appear to have used the ASTM International standardized diesel lubricity measurement. Credible? Sounded credible to me and certainly better than the usual recommendations with nothing to back them up. But you be the judge:

http://www.johnfjensen.com/Diesel_**...itive_test.pdf

This study has lasted the test of time from what I have researched.....not too many disagree. Those that I have read, have nothing to back them up or something to sell....

I am curious if other well founded studies have come up with anything different.

For those that have added all kinds of stuff to their diesel with no ill effects...great...shows you how tough they really are. Then again, billions of hours and miles are logged every year from high time engines with no additives at all.

[d design]

Surely used engine oil has metal shavings in it that will kill ur IP and injectors? Mad idea

[sailorchic34]

Originally Posted by psneeld

Then again, billions of hours and miles are logged every year from high time engines with no additives at all.

Ah, you have the cast studies documenting this of course. I'm betting there are many a long haul trucker adding magic juju juice to their diesel tanks. Many do burn the old lub oil too with no ill effects. Though more due to micron oil filters I'm guessing.

ULS Diesel does seem to have less Lubricity then LS diesel. For the older engines, Pre ULS, adding a small bit of oil to the fuel may reduce calls to the diesel mechanic.

I do agree that Oil additives to engine crankcase oils are of dubious value at best, as are most gas additives.