A fuel conditoner will not fix bad fuel in cold weather. Some help
lower waxing point in diesel fuel but to operate reliaby in cold
weather in a light diesel you need properly winterized fuel that is
mixed by the distributor with number 1 diesel during the winter. I
would think up in canada that they would have a grip on that but keep
in mind that it is not a easy task to keep one running reliable in
extreme cold weather. Forget the cnditioner and make sure you get fuel
for a good source and use 5w40 oil in winter and a long extension cord
to keep it plugged in when temps are near or below 0 because that old
Powerstroke is not a easy starter with no heat when below zero and
will run poorly for a while when it does without keeping the engine
warm.  Good Luck