How to Fix Diesel Fuel Gelling

by Diane Wilkoff
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Diesel fuel gelling can stop you in your tracks when you are trying to get out on a cold winter night. Gelling occurs when the temperature of the fuel drops so low that wax naturally occurring in the diesel begins to crystallize. You can undo diesel fuel gelling once it has happened, although it is preferable to keep it from occurring at all.

Step 1

Add a gallon of kerosene for every 10 gallons of diesel in the tank. Kerosene is a fuel similar to diesel; however, it has less wax and does not begin to gel until the temperature is lower than that of diesel fuel. If your diesel fuel has already gelled, and temperatures are below minus 20 degrees Fahrenheit, this amount should suffice. Give the kerosene time to blend with the diesel. Kerosene will spread out the wax and wax crystals. Your fuel economy will decline, but at least your vehicle will run.

Step 2

Apply heat to the fuel filter to break up the wax. A block heater is a good idea in very cold climates. It goes right into the engine block and keeps the coolant and oil warm. A block heater does need to be connected to an outlet to work. If you do not already have a block heater you can have a mechanic install one. Many diesels have them as standard or optional equipment.

Step 3

Add a cold flow improver or anti-gel fuel additive to your diesel fuel. These prevent wax crystals from forming and clumping together. You will need to add these with every new tank of fuel.

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