Diesel Don
First i would install a water heater so the engine would be warm to start with then change to amsoil for the winter also i would use a diesel fuel cetane to help boost the combustion of the fuel. also i would set the idle up a little higher for the winter.
I have done this when i have taken trips to utah in the winter. I have only had experince with the amsoil products and there is other products out there that should be able to do the same things.
Bill

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94 dodge cummings,86 ford 6.9,75 mbz 240d[ sold], 82 mbz 300sd,83 mbz 300sd