Diesel Fuel Life Expectancy

[redsky49]

Given the widely differing conditions under which stored (on board) fuel encounters, are there any guidelines as to the viable life of diesel fuel?

More importantly, is there any simple test a skipper could perform to determine the condition of the fuel?

Granted, really poor fuel smells different/bad, but I can't detect any obvious odors or any other signs to help me decide if my 16 month old fuel is toast or not. Is a visual exam sufficient?

Suggestions? Are there firms that will analyze mail order samples?

TIA

[MarkSF]

"Given the widely differing conditions under which stored (on board) fuel encounters, are there any guidelines as to the viable life of diesel fuel?"

Lifetime varies as much as the conditions. The good news is that Practical Sailor tested biocides, and found that they work. They also found that the two leading brands were each effective on differing bacteria, so they suggested alternating between them, every year or two. I'm on my second year with Bioguard, it's nearly time to switch to Biobor JF for a couple of years.

[motaman9]

I recently bought fuel in Morehead, NC. They were selling "Valvetech" treated fuel which they claim is guaranteed for a year without other treatment. It was the first time I'd seen it. The dockhand said that after the first year it can be treated with regular biocides. I guess we will see.....


Sailing somewhere.....

[MarkSF]

Valvetect (sic) are the maker of the Bioguard I'm using. Probably the same stuff in the fuel.

[motaman9]

Originally Posted by MarkSF

Valvetect (sic) are the maker of the Bioguard I'm using. Probably the same stuff in the fuel.

Good to know.....thanks !!


Sailing somewhere.....

[DeepFrz]

You not only need to be concerned with algal growth but also a decline in Cetane rating. You may want to use a Cetane booster as well as a biological additive.

I think usually if the fuel is clear is should be okay. If it is cloudy then maybe time to replace it. Today's diesel fuel is quite different than the diesel fuel of a few years ago and it may deteriorate more quickly than it used to. I don't know if a test kit will be worthwhile, it depends on how much you have I guess.
Diesel fuel tests

[a64pilot]

Diesel fuel if kept "clean and dry" and if anti-microbial additives are regularly added, and if the fuel is polished occasionally, then it's shelf life is pretty much indefinate.
Many stand by generator systems have fuel that is several years old
http://axifuel.wordpress.com/what-is...d-diesel-fuel/

[S/V Illusion]

Originally Posted by a64pilot

Diesel fuel if kept "clean and dry" and if anti-microbial additives are regularly added, and if the fuel is polished occasionally, then it's shelf life is pretty much indefinate.
Many stand by generator systems have fuel that is several years old
What is the average shelf life of stored diesel fuel? | AXI Fuel Systems Blog

Not quite. There are a number of API studies as well as some done by the U.S.Navy which conclude 6 months is the avg time in dry storage after which parrafins degrade and formation of other paraffins begins, both of which are undesirable.

Given marine fuel isn't stored in ideal conditions, the typical lifetime can be far less. No doubt we will hear some anecdotal exceptions but don't forget the guy who jumped off a 10 story building heard, while passing the second floor to say, "so far, so good".
begin.Biological degradation of diesel f... [Appl Microbiol Biotechnol. 1998] - PubMed - NCBI

[barnakiel]

Originally Posted by redsky49

More importantly, is there any simple test a skipper could perform to determine the condition of the fuel?

Turn the key?

We used some fuel that was some 4 years old recently.

Keep eye on the filters though. Just in case stuff sloshes at the bottom.

b.

[marlinmike]

I would pump a gallon off and pour some in a jar and hold it up to the sun, if looks clear I would burn it off like previous posted stated, if it has all kinds of crap floating around I would get a fuel polish guy down to clean it.

In the future if you have a valvtec station near by use it, it has multiple additives already premixed, cetan booster, bio-side and lubricity agent, worth the few dollars extra.

[MarkSF]

It's "Valvtect", btw. Not Valvetect, Valvetech, or Valvetec.

[DeepFrz]

Probably lot a large enough amount of fuel to bother with a fuel polishing guy when you can filter and clean your own fuel for a small amount of money. It is always a great idea to make sure your tanks are clean and cleaning them should be a maintenance item, IMO.

[thinwater]

a. Diesel varies in stability, according to refining process and base crude. One sailor's answer may not be another's answer.

b. Temperature, storage (temperature swings, tanks full vs. empty), and climate (humidity all matter, as others have stated. They can combine to account for 10-100x difference.

c. While appearance is important, "clear and bright" does not assure that the tank hasn't dropped solids or water that will be stirred up. But some people never really see rough weather, the baffling and placement of the tank are additional variables.

The surest test may well be to scrape a sample up from the bottom and see if there is any sludge. If it were me I would have an opening and clean the tank every 5 years or so. If it is not dirty, it will only take minutes.

[a64pilot]

Originally Posted by barnakiel

Turn the key?

We used some fuel that was some 4 years old recently.

Keep eye on the filters though. Just in case stuff sloshes at the bottom.

b.

I've got fuel down at the barn over ten yrs old, the ole JD410 seems to run fine on it, but it is old Diesel fuel, this ULSD stuff, is well, different. I don't know too much about it yet.

[Kenomac]

Install a fuel polishing system and run it regularly, then..... No worries.

Ours is a Reverso fuel polishing module 150 gallons per hour, custom installation run through a huge Separ filter/separator. We run it whenever we run the generator. Relatively small money to solve a potentially big problem.

You'd be surprised what filters out of apparently clean fuel.