I have lived most of my life in warmer climates so don't claim to be an expert but here are a couple of bits of info that might help.
In the RV transport industry drivers that deliver diesel motor homes are required to add anti-gel products to the fuel tanks when the temperature reaches 15 degrees Farenheit or below.
I have asked clerks at Flying J truck stops on several occasions in cold country when temps were low or expected to get low whether the fuel they were pumping was winter blend. The answer I received has been, "huhh?" They were clueless.
When I know the temp will get below 15 degrees I add Power Service. I discussed this with a friend recently who is one of the TDR contributing editors. He advised adding anti-gel to the main fuel tank when the truck will be parked overnight and exposed to temps in the low teens or below but said I could probably skip adding anti-gel during the day after it is started because the Cummins HPCR engine continually recycles warmed fuel back to the factory tank when running. Assuming that the sun shines on the black-painted 70 gallon Transfer Flow auxiliary tank in the bed I could possibly get away without adding anti-gel during the day but might want to to be safe.
I have not done it yet but I have read that a driver can pump equal amounts of No. 1 diesel and No. 2 diesel into his tanks to create his own winter blend. I may start doing this when I know I'll be fueling then parking the truck at the end of a day of travel.
Early this year, in January I think, I was pulling a 5er from IN to WA or OR. I spent a night at a motel in western NE. I plugged in my truck's block warmer but I didn't know the receptacle was dead. I managed to get my '01 Ram started without a block heater at -20 degrees but it was a close one. I had regular old Shell Rotella 15-40 oil in the crankcase. I had to keep the starter engaged as the engine slowly began running very poorly and very roughly but it did start and run. I was very grateful I had mixed Power Service in both tanks.
As I cruised across Montana that day it was a beautiful sunny day and the roads were clear but the temp dipped to -28 in the Rockies. I passed probably a dozen big rig trucks sitting on the shoulder that day, some of them shiny new tractors, waiting for road service. I didn't stop to ask but I assumed their fuel had gelled and shut them down. I was surprised. I expected that experienced big rig drivers understood the problem.
Harvey
Attention: TDR Forum Junkies 
