Mix auto transmission fluid in diesel fuel?

[Porchhound]

When I purchased my Chevy 2500 (used) my mechanic advised putting a cheap quart of transmission fluid with every 20gal of fuel during fill-up. Since then I've put 120K miles on the truck with no injector issues. Does this process make sense in a marinized diesel environment?

[Lou_tribal]

Question is would you have got 120K miles without doing this?

L

[psneeld]

If you get 500,000 miles....that may say something....Plenty of light truck diesels getting 300,000 to 400,000 without regular additives....but is part guess because many owners never keep the truck that long.

Additives may help, but not necessarily needed.... but I wouldn't use anything but a top couple.... not tranny fluid.

[Cigatoo]

ATF is an excellent cleaner. We also used it for years to dissolve internal engine carbon deposits. Probably can’t hurt anything and might help keep your injectors clean. If it makes you feel better it’s worth the effort.

[Porchhound]

Originally Posted by Lou_tribal

Question is would you have got 120K miles without doing this?

L

LOL kind of difficult to answer a hypothetical, but I trust my mechanic and he uses the ATF fluid in his nearly identical truck, and we both work them pretty hard pulling trailers, etc. I think his reasoning is the lowered quality of diesel today causing injectors to clog and pumps to fail.

[Dwk]

Seems to me if this is a beneficial practice there would be lots of chatter from satisfied folks. Following to learn.

[utclmjmper]

Some folks have been mixing two stroke oil also for a long time since the removal of lubricity in diesel..>>>Dan

[catalinajack]

Originally Posted by Porchhound

When I purchased my Chevy 2500 (used) my mechanic advised putting a cheap quart of transmission fluid with every 20gal of fuel during fill-up. Since then I've put 120K miles on the truck with no injector issues. Does this process make sense in a marinized diesel environment?

I don't know if it makes sense but I do know that the fact that you have had no problems in 120,000 miles means absolutely nothing. You would be better off using a lubricity improver rather than following some shade-tree mechanic's ignorant advice.

[Swede 1]

It's not being used for lubricity but for its detergent properties. Fairly common practice amongst the so called "ignorant shade tree mechanics" as well as the 2 stroke oil for lubricity.

[Porchhound]

I don't think it's that common, but when I've mentioned it to different mechanics they seem to agree additives are beneficial today. I'll just keep doing it, probably out of habit at this time. Truck has a total of 155k, small potatoes for a diesel, but I hope to keep it running for at least another eleven years.

[Porchhound]

I hadn't heard about the two-stroke oil, but makes sense today.

[North Baltic sea]

Hi,

if it would be good for a diesel engine, then i would think this information can be found in the manuals, i will just find there "do not add additives" to the oil or fuel.

Hard to believe that Cummins would instruct you to shorten engine life.

Here, the fuel is at least additive lubricated by the injection pump / nozzles, hard to believe you wouldn’t have this in the US.

NBs

[Simi 60]

Originally Posted by Cigatoo

. Probably can’t hurt anything

Probably isn't very convincing

and might help keep your injectors clean

.

Might isn't either

If it makes you feel better it’s worth the effort. ]

Until it's not

[O C Diver]

Originally Posted by Porchhound

When I purchased my Chevy 2500 (used) my mechanic advised putting a cheap quart of transmission fluid with every 20gal of fuel during fill-up. Since then I've put 120K miles on the truck with no injector issues. Does this process make sense in a marinized diesel environment?

I now have 517,000 miles on my Dodge pickup with a Cummins 6BT 220 HP engine. Never used any additives. It would be interesting to know the history of diesel fuel formulation over the last 50 years. While most are aware of the removal of sulfur which acts as a lubricant, it would be interesting to know what other properties have changed. You have to wonder what other changes were made to be compatible with tier 3 and 4 diesel engines.

The other thought regarding adding ATF to the fuel is whether that effects other things in the fuel formulation. While I can respect a mechanic, I'd rather have someone do the science to see how it effects diesel from tank, through the engine, and out the exhaust.

Ted

[AlanT]

Originally Posted by Porchhound

When I purchased my Chevy 2500 (used) my mechanic advised putting a cheap quart of transmission fluid with every 20gal of fuel during fill-up. Since then I've put 120K miles on the truck with no injector issues. Does this process make sense in a marinized diesel environment?

I would be more inclined to take advice (if at all) from a commercial semi-truck fleet manager. They typically maintain detailed records, take oil samples and if they are finding the use of additives is beneficial I would be intrigued. I personally would not add anything to my fuel based on solitary or anecdotal recommendations here or elsewhere, rebuilds are too expensive.

On another note, a well maintained diesel is likely to outlive any recreational user's usage.

~A

[Porchhound]

Originally Posted by North Baltic sea

Hi,

if it would be good for a diesel engine, then i would think this information can be found in the manuals, i will just find there "do not add additives" to the oil or fuel.

Hard to believe that Cummins would instruct you to shorten engine life.

Here, the fuel is at least additive lubricated by the injection pump / nozzles, hard to believe you wouldn’t have this in the US.

NBs

Manufacturers of engines seem to always warn against additives, irrespective of changes in fuel quality because they can't control what you may introduce to your equipment. Besides, they love to void their warranty exposure whenever possible. Low sulfur diesel is bad for engines. Unleaded gas with ethanol is destructive to small engines, yet garden tractors/mowers, etc all warn against using lead additives or alternative fuels (I use leaded gas). The local small engine repair shop recommended it.

The "shade-tree mechanic" I use has kept cars and trucks and farm equipment running in this agriculture community for over forty years. He knows what current fuels do to engines. If he uses ATF in his personal vehicle, I'll call that good.

My question had more to do with diesel engines operating in a marine environment. These old marinized tractor engines, like i have, weren't designed to operate on low-sulfur, low lubricity fuels. Maybe the new diesels are.

The only "additive" system I know of on a diesel here in the states is the DEF where ionized water and urea are sprayed into the exhaust system to cut down on pollution. Owners hate it...just another system to have to monitor.

[Art]

OK - here's a little bit of hijack... but along the same lines regarding an additive:

For older gasoline engines: It is good to add 4 oz. ZDDP at each oil change [actually, I also put in an extra 4 oz. mid way between changes].

Reason - Older gassers need zinc in their oil as a barrier-film between bushings... ya know... flat tappets to cam shaft lobes and the like. https://en.wikipedia.org/wiki/Zinc_dithiophosphate

Anyway... I've currently got five pre catalytic-converter V-8's in different rigs. They all run sweet and use no oil. One 1967 430 ci 360 hp., two 1977 350 ci 255 hp., one 1985 350 ci 325 hp. and a 1996 454 ci 300 hp.

[TBill36]

Find out what some of the long-haul truckers are adding if anything. That's where the real pay-off and experience is.

[Porchhound]

Originally Posted by AlanT

I would be more inclined to take advice (if at all) from a commercial semi-truck fleet manager. They typically maintain detailed records, take oil samples and if they are finding the use of additives is beneficial I would be intrigued. I personally would not add anything to my fuel based on solitary or anecdotal recommendations here or elsewhere, rebuilds are too expensive.

On another note, a well maintained diesel is likely to outlive any recreational user's usage.

~A

Over-the-road trucks use D2, a very different type of diesel which is less volatile. I'd be curious how that affects their engines. I know they get better fuel economy with it.

[Porchhound]

Here is a link to a Canadian website for truckers. Note they state that diesel fuel in Canada is better quality than in the states and that "most" Canadian truckers would admit to using additives.
https://www.trucknews.com/transporta...ve/1003123578/