I have an indoor standby diesel generator that has a full 50 gallons of fuel in it.
The fuel is about 4 years old.
Does diesel fuel have a shelf life?
Should I transfer it to the Dodge and use it up and re-fill the generator with new fuel or let it be?
What do you folks think?

 

As long as the tank was full and stayed that way the whole time it will be fine. The problems start when you have a half full tank. Things start to gum up from oxidation, you get condensation making water in there and all sorts of nasty related collateral damage happening. But if it was full, good to go. Either use it or keep it that way, but don't leave it partially full. I'd probably recycle it every five years just to be on the safe side anyways, though.

 

Older high sulfur used to keep almost forever. When 500 ppm fuel came out in 1995 the shelf life was reduced dramatically to sometimes less than a year depending on conditions.
Not sure on the life of the new ULSD but my bet is shelf life has been reduced even further.
If it was me I'd rotate it into my truck at least yearly.

 

Good advice from all.

I would use it, but mix it with new fuel as you go. Start with a 30% old 70% new and build up to 50/50 over a few tank fulls. I would stay at 50/50 just to be safe. You don't want to gum up a good engine.

JMHO

 

I've run fuel that was about ten years old and old heating oil that was twenty years or more old. No problem.

But, as stated earlier, if it has moisture and algae in it, don't transfer that stuff without filtering it first. If it looks clear as you drain some, then use it as normal.

I like old fuel. It's the real deal. Lot's of energy and lubricates well.


John

 

Im with Geico... If the fuel looks normal, I would just add about 5 gallons to your next 10 tanks or so, then refill the generator with new fuel... How old is the generator? I would assume the new ULSD would not negatively effect it? Maybe someone else would know more

 

When you get the fuel, take it from the top.

Water will sink to the bottom since oil floats, and Diesel is nothing more than thin oil.

phox