part of the problem is that once the fuel gets cold in the suppliers tanks the wax crystals have already formed. 99% of the fuel additives out there are only designed to PREVENT wax from forming. They do NOTHING to break it up. Diesel 911 and 1 product from FPPF are the only ones I know of that claim wax breaking capability. Since your truck has relatively warm fuel in the tank and lines when you stop to fill up it usually can gimp along and naturally warm up the new fuel above the cloud point. however if the truck is parked before the fuel warms up enough to break up the wax, it's just sitting there waiting to cause issues the next time you start it. Steam or really hot water from a pressure washer on the filter housings usually will break up the wax enough to get it going, especially if it's not frozen solid. I have also heated the filters with what you americans call a weed burner (proper name Tiger Torch). You don't want to even get close to scorching paint just warm enough to get it well above 32F.