Winter’s approach brings truck fueling systems into a different focus. Although fuel filters and water separators get routine checks year round, as ambient temperatures begin to drop, the actual fuel in the tank requires more attention.
When temperatures begin to fall, the quality of fuel plays a big factor in how quickly it begins to fall out of spec.
Ultra-low-sulfur diesel No. 2 contains natural combustible paraffin wax molecules, which make up a portion of the fuel’s energy content. Colder weather can cause the paraffins to drop out of the fuel and gel together, causing the fuel to become cloudy, otherwise known as the Cloud Point. As temperatures continue to drop, lumps of gelled paraffin can form larger chunks, restricting fuel flow, clogging filters and causing the Cold Filter Plug Point (CFPP).
Indicators of gelling include hard starts, loss of power and decreasing miles per gallon.
Rob Howes II, executive vice president for Howes Products, said a quality preventive anti-gel additive works by modifying the shape and structure of the naturally present wax paraffins in diesel fuel, encapsulating them to prevent them from binding together when they inevitably fall out of the fuel at extreme cold temperatures, allowing the wax to pass through fuel filters despite having fallen out of solution.
“This is why even treated diesel fuel will look cloudy at cold temperatures,” Howes said. “Even the additives themselves will have a cloudy appearance at cold enough temperatures. This is all part of the process.”
According to fuel supply and logistics provider Mansfield Energy, the difference between the Cloud Point and the CFPP varies depending on geography and fuel quality. When treated properly with winter cold flow additives, however, the CFPP will be about 18 degrees below the Cloud Point. For example, if fuel is treated with additive and gets cloudy at 10 degrees, then filters will plug at -8 degrees.
