Oil & Fuel i need help!!!!

[WilliamTO-35]

While not an answer to your diesel cold weather problem, I do agree that seasonal fuels can cause trouble. Last summer, I started using gasoline I had bought in the winter in my riding mower ( Kohler 14 hp. K321 motor). The gasoline was too volatile for hot summer days, and was boiling in the carburetor, and causing the engine to run rough and stall. I bought some summer gasoline, and the problem disappeared. I later installed triple thickness gaskets under the carburetor mounting flange to help keep the carburetor cooler. I used up the winter gasoline later on in the fall weather without problems.
As for your diesel fuel gelling problem, I would think that the additives truckers use to prevent gelling would work, unless there's water in that fuel. Put a gallon of the diesel fuel into a clear plastic jug, and let it sit for 24 hours someplace where it's above freezing. Water will settle to the bottom. As suggested above, a slight dilution with kerosene is also sometimes used.
You might actually do better trying to use #2 home heating oil, although the local supply of diesel and heating oil may come from the same source. The heating oil may work fine as is, but you could try adding a cetane improver and gel preventative to the heating oil if you encounter diesel knock or gel problems. The "powers that be" do get very upset if you use heating oil without paying the road tax, but as a temporary experiment it might be informative.

 

[ScottW]

I had fuel problems today while snowthrowing after a few weeks of inactivity. After running fine for 15 minutes, the engine just stalled out, and although it would restart fine, it would choke out within a few seconds each time. After a couple false leads from my dealer to diagnose the problem, I finally took off the fuel filter housing and was greeted with a bunch of white goo. I put another filter in, drained the air, and it ran fine. I'll warm the old filter back up, dry it, and save it for future use. Now I need to go get some additive for my 2/3 tank of diesel that is mostly summer fuel. My refueling can is winterized diesel, but the tractor sips fuel, so I haven't had much chance to use it yet. A long spell of cold weather with lows below zero finally did me in I guess.