Diesel fuel can gel in cold temperatures because it contains paraffin wax. At 32 degrees Fahrenheit, the wax will crystallize and leave the fuel tank clouded. At about 10 degrees Fahrenheit, it will start to gel and clog the tank and fuel filters.
Although anti-gelling additives will not hurt diesel fuel or the engine, kerosene works just as well and is usually more cost-effective. Adding one gallon to each tank will keep fuel from gelling and is more economical than additives. Colder weather states will have anti-gel additives added to their bulk tank to prevent gelling. Try not to fuel south of Tennessee when headed north.
Make sure to run off the top half of your tank. Tanks with more fuel have less chance of forming condensation and turning into ice or gelling. Make sure that fuel tanks remain topped off, especially before driving through remote areas or on secondary highways.
The rule for idling at cold temperatures is called the “10 & 2 Rule”: If is 10 degrees Fahrenheit or less and the truck will be sitting for more than two hours, IDLE. This will help to prevent fuel gelling, icing, thickening of motor oil, and freezing of batteries. Fuel lines will gel before the tanks so keep the engine running and the fuel moving.