Does Fuel Oil Go Bad?

[Weho Dave]

I filled up my heating oil tank in November for $450 and didn't use a drop. Burned wood all winter. It is still full and I am wondering if the oil will go bad if I don't use it. Does anybody have any experience with this?

[Wendy]

We often have leftover fuel oil from year to year & have never had any trouble. Our tank is about 3/4 full right now & we won't use it again until October.

[fordy]

Originally Posted by Weho Dave

I filled up my heating oil tank in November for $450 and didn't use a drop. Burned wood all winter. It is still full and I am wondering if the oil will go bad if I don't use it. Does anybody have any experience with this?

..........Fuel oil\Diesel fuel , will last for several years , IF treated with the life extender . For instance , some cell phone towers in remote areas have diesel generators to power them if the grid power goes out and their diesel fuel tanks are tested and treated , if necessary . Gas on the other hand will start to decompose chemically in short order . fordy...

[Obser]

Here is a discussion by Emory Warner in Backwoods Home Magazine. The article contains other useful information about fuels and storage. http://www.backwoodshome.com/articles/warner43.html

Diesel fuel stores almost as easily as kerosene and is becoming more and more popular among the self sufficient. It is difficult to ignite intentionally and almost impossible to ignite by accident. Two grades are available: #1 diesel which is old-fashioned yellow kerosene, and #2 diesel which is the same thing as #2 home heating oil. (You may see literature to the contrary, but #2 diesel is #2 heating oil. Period.) Diesel fuel presents its own unique storage problems: The first is that it is somewhat hygroscopic; that is, it will absorb moisture from the air. The second and related problem is sludge formation. Sludge is the result of anaerobic bacteria living in the trapped water and eating the sulfur in the fuel. Left untreated, the sludge will grow until it fills the entire tank, ruining the fuel. Stored diesel fuel should be treated with a biocide like methanol or diesel Sta-Bil as soon as it is delivered. Unique to #2 is the fact that some paraffin wax is dissolved in the fuel and will settle out at about 20° F, clogging the fuel filter. This “fuel freezing” may be eliminated by adding 10% gasoline or 20% kerosene to the diesel fuel. Commercial diesel fuel supplements are also available to solve the same problem. Diesel should be filtered before use.

[Ross]

Heating oil/diesel can go bad if there is water present. Bacteria grows in the oil feeding off it and leaving a sludgey foul smelling puddle on the bottom. Actually the foul sewage smell rises so you can tell if you oil is going bad from the vent cap. It will certainly keep for a year or two or three. Oil from a distilate process lasts longer than cat cracked versions but you wouldn't know which you had! #1 is winter diesel and Canada has a #0 Arctic heating oil. #2 is heating oil or diesel #3 is a defunct designation, #4-#5 are industrial oils and #6 is good old bunkerC, whats left after that is made into asphalt etc.