aFe DFS780 Fuel System Cold Weather Kit | Fits DFS780 / DFS780 PRO (42-90001)DFS780 Fuel System Cold Weather Kit by aFe. Make sure your diesel is prepared to perform in the coldest conditions with aFe's DFS780 Fuel System Cold Weather Kit. The kit works with DFS780 and DFS780 PRO diesel fuel systems and easily plumbs into your engine's cooling system to warm the fuel to keep it from gelling in freezing temperatures. Heater hose not included. aFe (Advanced Flow Engineering, Inc.) manufactures performance products for late model