This past winter, I wasn't running any cold weather diesel fuel additive because it had been prety warm.
But, there was a week long Montana cold spell (-20's) when I was out of town and my truck had to sit all alone in the cold.
When I got back, I plugged in the block heater overnight. In the morning the truck started right up, and idled fine. As I was scraping the snow from the windows, the idle started geting loappy like something with an agressive cam shaft. I checked out the fuel pressure warning light and it was glowing bright red. I shut down the engine and tried to thaw the fuel filters with my wife's hair dryer. Ater about an hour of trying to warm them and occasionally trying to run the fuel pump (by engaging the starter momentarily then releasing the key before the engine starts), I couldn't get the low pressure light to go out like it normally does when the Air Dog primes the system. I didn't want to risk ruining my freshly replaced VP44 from low lift pump pressure, so I had to just leave my truck to thaw out when nature decided it was time. Luccaly we had a couple of days in the 40's and that was all it took to melt the wax or gel or whatever had clogged up my Air Dog.
I kind of had to learn the hard way that the Air dog doesn't have a fuel heating function specifically for the cold weather like the factory system did. I now know I need to run a good winter fuel additive all winter long. I doubt that a 10 micron filter would have ben enough to have "fixed" the diesel gelling in my fuel.
On a side note, when I drain the water trap on the Air Dog, sometimes I see what seems to look just like the Wallmart 2 cycle oil that I add during fillups. Isn't that stuf supposed to get mixed up when you add the fuel after dumping in a quart of 2 cycle oil? Do you guys think the water trap is sepperating it out because that stuf is heavier than diesel just like water?