Approximately at what temperature does diesel start to wax?
 

I'm in the southeast now, but when I lived in the northeast and the temperature would drop to the teens or lower, I had an Amoco gas station that sold the best diesel and I would cut it on fill ups with either K-1 white kerosene or K-2 brown..... and NEVER had fuel gel/waxing problems...... In the southeast it's not so easy to do as the temps rarely drop that low but occasionally they do!

So, my ultimate question is when does diesel start to gel. at what temperature and or wind-chill does this occur???

Thanks

It depends on the fuel mix. Go to a high volume truck stop and ask them what their current fuel mixture is rated for.
I have not had a fuel gelling issue since 1990 when I filled at a low volume dealer that still had summer blend. It was -20 that night.

Windchill has no effect on how "cold" inanimate objects get. Wind can reduce the time it takes to cool an inanimate object down to the ambient temperature, but it cannot get it colder than the ambient temperature. So if it is 20 degrees out and the windchill is 0, the coldest that your fuel can get is 20 degrees.

Gel point is the temperature at which diesel or biodiesel fuel freezes solid and can no longer flow by gravity or be pumped through fuel lines. This phenomenon happens when a fuel reaches a low enough temperature whereby enough wax crystals have formed to prevent any movement in the oil. For #2 diesel this is usually around 17.5 °F (−8.1 °C).

For the fuel to become pumpable again, it needs to be brought above the gel point temperature to the Ungel point, which is typically near its pour point. However, most of the waxes will still remain in solid form and the fuel has to be warmed up further until its Remix temperature in order to completely remelt and redissolve the waxes.

Anti-gel additives are therefore commonly added to diesel or biodiesels where cold temperature is expected. They act to reduce the formation of wax crystals in the fuel, thereby lowering the pour point and the gel point of the fuel. Anti-gel additives may not necessarily affect the cloud point.

I have had my '82 300D in Augusta for over 22 years. I have never experienced a gelling problem that I was aware of.

From December through March I purchase my diesel from the local farm co-op that fuels the school districts busses. They say it is good to -30, they can't have a bunch of busses with students on rural roads with issues, or no starts in the AM. It is about a dime per gallon more than lowest priced fuel in town, but $1.50/wk extra is fine by me.

As others have said, it depends on the mix. High volume fuel stations SHOULD(!!!!!) be selling a fuel mix appropriate to the conditions foreseen.

I have a buddy who's a truck driver, they fuel at the local truck stops and his company instructs drivers to start adding antigel to fuel around the ~15 degree range. If they've done the studies and such on operating conditions and are willing to spend the money on antigel at that point(although buying in an IBC tote, they spend less per gallon to treat than we do), that's good enough for me. I personally add antigel when it's below freezing, as the temps around here can easily drop 15 deg unexpectedly and I don't turn over the fuel in my tanks like those guys do. They're going through a tank per day minimum, and I could have fuel from two weeks ago in my tank. Cold snap that wasn't even on forecast back then hits and bam, tank, lines, and filters full of butter. I also try and fill up at the B20 station, and while I'd expect them to have a mix that won't gel or be adding the proper additives, I also know biodiesel gels at a higher temp than dino and I don't want any issues.

Never had an issue. Does that mean if I did nothing I'd never have an issue too? No clue, but for the minimal cost and hassle, I'd feel awfully silly having to defrost my truck inside the shop.

Curious now, think I'm going to take an untreated sample, leave it out, and see what happens.