I've used diesel fuel for years, running well over 700,000 miles on three different diesel engines of my own; a '78 Mercedes 300, a '98 6.5 Duramax, and my current '08 6.6 Duramax.
I don't profess to be an expert on fuel additives, but was guided early on by a Mercedes mechanic, and then later by two different diesel fleet mechanics. I like
Standadyne or
Lucas Fuel Conditioner, which one diesel fleet mechanic said are pretty much interchangeable. Lucas is more readily available, so I've used it almost exclusively for the last eight or so years.
I buy Lucas by the gallon at a independent truck stop in TN (where it is always about $2/gal cheaper than chain truck stops) and decant it into an old 16oz plastic Stanadyne bottle to keep in my drivers door for adding at each fuel stop. Just a couple ounces per fill-up. Originally started using it when the Ultra Low Sulphur fuel came out because my engine was pre-ULSD, then researched it when I got the current Duramax and have kept using it for it's lubricity. Some users will spout off all sorts of tech figures etc, or make some pretty outrageous claims, but I have no tech stats or huge claims. I can just only honestly say the diesels run smoother and better using the fuel conditioner, as if they're working easier with less friction.
For winter fuel, and I've run a
lot of northern miles, from Minot to Caribou, I most always have used winterized fuel when I can and have not worried too much about adding additional anti-gel additives. Sometimes will add
Red Line anti-gel. Block heaters help too, though I realize that is rarely an option when expediting.
My current Duramax, the '08 6.6 (only had two winters with it), has a more advanced starting and glow plug system than did my other engines and has had absolutely no problems yet with starting in cold weather, even without winterized fuel. More important has been to keep the batteries good.