Tips to Winterize Your Backup Generator Fuel System


The days are getting shorter, the nights are getting cooler, and winter will be here before long. Today, we’ll go over some tips to winterize your backup generator fuel system.

Diesel fuel undergoes certain changes when the temperature drops. Paraffin wax will precipitate out of the fuel, then the fuel will solidify into a gel. When paraffin starts to solidify, this is called the cloud point, since the fuel will take on a cloudy appearance. The gel point is reached when enough wax has precipitated out of the fuel so that it no longer flows. The gel point is usually 10-15 degrees below the cloud point. When the fuel starts to cloud, it can clog filters and choke your system. In the past, this was not as much of an issue because of different legal requirements regarding fuel chemistry. The new, lower-sulfur diesels that are mandated by the EPA have changed this fuel chemistry dramatically.

Another problem to consider is the presence of water in your diesel. Again due to the lower sulfur regulations, higher concentrations of water in fuel have occurred. Water also occurs when moisture hits warm fuel inside a cold tank, causing condensation to form. At low enough temperatures, this water turns into ice, causing damage to your filters and fuel systems.

In order to prevent issues from arising, the following steps should be taken:

Dry out your system. Use a water-removing isopropanol fuel additive that will pull any existing water out of your system. Your tank should be at least halfway full for the treatment to work effectively.
Change your fuel filter. An old filter will clog much faster than a new one.
Use a winter fuel additive. Winter fuel additives combat both water and wax suspended in your diesel, keeping it from clouding or forming ice crystals.
Inspect fuel lines. Ensure that there are no blockages, and that everything is working properly.

In addition to taking the preventative measures outlined above, your fuel should be changed out from summer diesel to winter diesel. What’s the difference? Summer diesel will begin to cloud and gel as the ambient temperature drops below freezing. When the temperature gets below 0F, the solidifying wax particles combine into solids large enough to clog filters. Winter diesel is a blend of summer diesel and a mixture of diesel and kerosene. Kerosene actually lowers the gel point in winter blend diesel, and the actual gel point will depend on the specific blend purchased. The higher the kerosene content, the lower the gel point.