Is 4 year old diesel fuel any good?

[chim]

I am friends with a BIG TIME operator in my area. He got a 5,000 gallon diesel tanks off a big milk & dairy producer for $0!!!
The dairy producer had huge new Cummins diesel generators installed, and the installer refused to give them a warranty on the generators unless the old tank and fuel was removed And new ones installed.
So my farmer friend got the tank & remaining fuel in it for nothing. He just had to remove it from their facility and bring it to his farm.

Just thought it was interesting that the generator company would not give a warranty on gen sets unless they had NEW tank and NEW fuel. They said too much risk that injectors and pumps could be ruined.

Generator reliability. Reminds me of a call we got form a hospital almost 30 years ago. There was a power failure, and after running for a while, the generators shut down. Very big deal.

Power came back and the generator vendor came and got them up and running. Then they simulated failures without finding what happened. The hospital maintenance staff said the generators ran out of fuel (but they had thousands of gallons in underground tanks).

Our technician discovered the flaw. These big gensets have "day tanks" in the generator room. The fuel needs to be pumped from the storage tanks to the day tanks, which then feed fuel to the gensets. The pumps that transfer the fuel from the storage tanks to the day tanks were on NORMAL POWER.

 

[mwayne]

Snobdds in post #15 has a great idea. With luck from the utility and weather, some of our generators may take 10 years to run through a tank of diesel. Our fleet manager hired a company to polish the generator fuel on a regular basis and that has worked well.

 

[Texasmark]

I pump our of 55 gallon drums with a Tractor Supply 12v pump. The tube that sticks into the tank stops about 1 1/2 inch from the bottom. Every time I fill up I get a flash light and peer at the remaining fuel looking for water, crud or algae. On the output of that pump I installed a final filter just in case.

 

[Jerry/MT]

I buy bulk fuel. 2400 gallons at a time. typically lasts 2 to 3 years before I need a refill. I try to time my purchase for tax spending and low points in the oil market (none election years). I have been doing this for 20 years and have not ever had any issues with fuel quality. I do run a filter on the pump and a Hydrophilic breather to keep out moisture. My tank is epoxied on the inside with a manhole flange for inspection, but I have never taken it off and inspected. I hear a lot about algae problems but I think that in the absence of sunlight algae can not grow and thrive.

I have had diesel turn to varnish on a machine that was parked for 8 years, but the varnish was all in the lines, when I drained the tank the fuel was fine outside of some water and no strange odor. I think the varnish had to do with the rubber hoses breaking down and some chemical reaction occurring.

"Algae" are not the cause of fuel degradation since algae are plants and need sunlight to live. Bacteria that live in the fuel/water interface in a diesel tank cause the problem. No water, no bacteria.

 

[r porter]

take a sample and have it tested. find out if it is ok.

in 1972 i had 24,000 gal of fuel put in the ground for a generator. it cost 13.5 cents a gallon.
every year it would be tested and once in a while a gallon or two of inhibitor would be poured in the tank.

when i retired in 2003 it was still being used.

 

[Hay Dude]

I don’t think there’s much argument that under the right conditions or with the right treatments and clean tanks with no moisture that diesel fuel can last a long time. It can.
The problem is, we don’t know exactly what conditions the OP has. Maybe there was water in the tank previously, or rust particles, etc.

Related: A tech I know very well was stumped on a no-run on a tractor and figured he’d check all the normal things like water in fuel, filters, etc. Wouldn’t run.
Finally the found that the fuel line was plugged by a dead bug that was trapped in a fuel line.

It must have fallen in the tank during a refill.

My experience with bad fuel was I was running out of fuel and there was a tank that belonged to the previous occupant of my current shop. Typical diesel tank with an electric pump. I was in a jam , and just needed a few gallons. Within weeks, I had injector issues. The following year, I had to replace them.

Now I’m real cautious about fuel.

 

[jedigene]

I have about 75 gals of 4 year old diesel fuel and am wondering what I should do with it.

The fuel has been sitting in the fuel tank of a diesel pusher motorhome fuel tank. The fuel tank is 150 gals, or about 1/2 full. The motorhome has been always stored inside an insulated metal building located in a dry climate area.

I don't know if there are any problems with the fuel, and I don't know how I would test it or find out. The motorhome starts and runs fine. But I've read that old diesel fuel can have water or algae in it that clogs filters or does damage. I don't want to do that. Can you help with any ideas?

Here are the options I am considering:

- do nothing and just use it.
- siphon it out, replace with fresh, then slowly use it up/blend it elsewhere by adding small amounts when refueling my tractor.
- siphon it out, use for burn piles (but that's a LOT of fuel for that use!)
- put some additives in it and just use it.

The motorhome engine is a Cummins ISX. It is expensive to work on, even if just buying new filters. So I'd like to avoid causing any maintenance or damage.

Ideas?

Add

SAFECASTLE PRI-D Fuel Diesel Treatment for Lubricity & Stability Improved Performance, Maintenance, and Emissions Reductions, Maximum Lubricity Protection, Super Concentrated & Safe​

It is said to actually restore old fuel. I personally haven't used the Pri-D but I do use the Pri-G which is for gasoline. So far I haven't had any problem with it.

 

[jgmo]

Algae grows in water, not fuel. So, no water, no algae.
Having said that though....
Fuel sits atop water. That means IF there is water in your tank, it sits at the bottom. Right where the end of the pick up tube for your lift pump is.
So....water in tank means that water AND any "bugs" (algae) in that water will be immediately pumped to your engine.
How does water get in the tank in the first place?
Well, first off, ALL pump fuel has a bit of water in it. So....you get a little to maybe some more, anytime you fuel up depending on the place you pump from. Not a big deal really because you have at least two filters and, often, a water trap.
But...when you let it sit for years, the water can actually increase due to condensation from the atmosphere as your tank "breathes" through the vent system.

So....
You end up with the water you started with plus accumulated condensation.
That's what determines how much algae you may have grown over time.


Long haul trucks can travel 1 million miles with little to no algae problems. But, for example, boats that mostly sit at the dock with a fuel load can grow copius amounts of algae in their tanks.

It's bad because the condensate moisture tends to cling to the tank walls and algae will not only grow in the water at the bottom of the tank but also on any exposed surfaces inside the tank.

As a result, a tank that is half full will grow more algae over the long storage time than one that is full of fuel.
That's why you may have heard the term "tank polishing". It's often required to clean/scrub the algae from the tank walls.

Old fuel can be "polished" too by running it through filters at elevated temperatures to clean it and remove the moisture. It's expensive though and usually only done in very large batches.

So, as someone else has already said, don't end up spending $thousands$ to save hundreds.

If you're lucky, your tank came with a drain plug. You could choose to drain some if so and have a look at what you might be up against.

Siphoning will NOT give you the same information unless you can figure out how to siphon directly from the tank's sump.

And, neither method will tell how much growth has taken place on the tank's walls.

Good luck.

 

[oldpilot]

My father-in-law used to throw any dodgy fuel into his tractor to burn it up. Of course that was before alcohol in gasoline, and the tractor was a 1950s Allis Chalmers.

 

[djengr]

All
I agree with just get new fuel, not worth the effort or risk.

However the curosity in me wants to know if this fuel has moisture in it. Where used to work we would always fight water in the oil (steam turbines) We would do a simple crackle test. Take a few drop of the oil/diesel and put it in a spoon or frying pan, heat it up and see if it boils. Moisture will boil before the oil burns.

I have a motorcyle that does not get used, sits in the garage, the last time I changed the oil it was full of water, I did the crackle test to verify.