Diesel fuel is sensitive to temperature. All diesel fuel has a certain amount of heavy paraffin-like components, which are high in energy value and help improve fuel economy. But, when temperatures are less than about -7 °C (20°F), these heavy paraffin components begin turning into wax flakes. If temperatures are low enough, these flakes can build up on the fuel tank filter or the engine fuel filter and stop fuel from reaching the engine.
At low temperatures, wax flakes are more likely to form in Number 2-D fuel than Number 1-D (or a “winterized” 2-D) fuel. For best operation at temperatures below – 7 ° C (20°F) use Number 1-D, or Number 2-D which has been blended with Number 1-D for winter use.
If you are driving in temperatures less than – 1 8 °C (0°F) and do not have Number 1-D or “winterized” Number 2-D fuel in the fuel tank, kerosene can be added to reduce waxing. Kerosene should be added at a ratio of one gallon of kerosene to two gallons o f diesel fuel. Because of the lower energy value of kerosene (and reduced fuel economy) it should be added only when anticipated temperatures are less than – 1 8 °C (0°F). Once kerosene has been added the engine should be run for several minutes to mix the fuel.
The addition of kerosene will not unplug a filter plugged with wax. Warming a “waxed” filter 0 °C to 10°C (32°F to 50°F) will return the wax to solution. Filter replacement is not normally required.
To improve cold weather operation, an engine block heater and fuel heater are on your diesel engine. (See “Cold Weather Starting” under “Starting the Diesel Engine” in Section 1 of this manual for information on the block heater.) The fuel heater is designed to come on when the fuel temperature is less than 4°C (40 °F). It warms the fuel and helps stop wax flakes from building up in the fuel filter.
