Diesel Fuel Anti-Gel Explained By:  Chuck @ Duluth Diesel http://www.twinportsales.com All diesel fuel inherently has water in it. That is why your truck has a fuel/water separator built into the fuel filter assembly that you periodically have to drain. Two things happen to diesel fuel in the cold.   The paraffin (petroleum wax) component of the diesel fuel will polymer together, forming a wax layer in yo