35 Year Old Diesel

[F4RM@11]

We have a sheltered fuel tank with diesel in it that's at least 35 years old. First off, does diesel gum up like gas does with time? Second, if it's not gummy and still clean and very much fluid, would it be suitable for using to flush a transmission per the procedure listed elsewhere on the forum?
 

[Janicholson]

If nice and clear, I would run it mixed with new diesel. Filter it to keep rust flakes out, but value is value. Jim
 

[F4RM@11]

I haven't looked at the fuel yet, but just had the thought today. I'd hate to spend retail on fresh diesel just to be drained and discarded, as most would agree.

I'll explore this more next spring when it warms up again.

Thanks.
 

[Bob M]

Diesel does not "gum up" over time like gas. However under certain conditions of condensation + warm temperature it can grow algae.

But as long as it still smells like diesel(or even if it doesn't...) old diesel it'll work fine for a tranny flush.

Suggest before using the old fuel dump it into 5 gallon buckets and let it sit overnight to settle out any water, rust, etc. Then pour the fuel off the top of each bucket and discard the last inch or so at the bottom.
 

[Wardner]

Just about everything, with the exception of solvents, settles out of diesel fuel. I have been running reclaimed home heating oil in my diesels for five years. Some of that fuel was old when I pumped it out of cellars and it's not getting any younger. There is no crap in my engine filter canisters.

I also have a DT466 in my semi-retired bucket truck with 150 gallons of fuel tanks. The last fuel I put in that truck was 14 years ago. It starts and runs fine.

So if you are concerned about cleaning parts, don't be. How dirty do you think the solvent is in a repair shop's parts cleaner?

BTW, when you are finished using the diesel fuel to clean parts, let it settle for a month and put it in your diesel tractor's fuel tank.

How are you going to "discard" it. Dump it down the toilet? Probably not. Garages with waste oil heaters should take it.
 

[F4RM@11]

As far as discarding, I have a local farmer who burns waste oil to heat his shop. Nope, it NEVER goes down a drain.
 

[TJV]

withthe way fuel seems by todays standards it may have degraded over the years but may very well be better than todays newly refined diesel. It will probably smell different and the exhaust will smell different because years back they started removing sulfer from fuel but the sulfer was a good lubricant (for injector pump parts)and produced a different smell than todays ultra low sulfer fuel.
 

[David G]

That should be fine to use in an off road older diesel. I would filter it when you pump it into another tank.

Do not use it in a vehicle that pays road tax, nor a newer low sulphur diesel. The DOT frowns on seeing red Diesel in a tank.
 

[rustred]

perfect for flushing trans. no it dont gum up. just gets an old smell to it.