Most construction work involving heavy machinery happens outside. And just as people tend to eat lighter in summer and switch to stick-to-your-ribs food in cold weather, that equipment needs different fuel in different seasons, too.

Summer fuel is all about performance and fuel economy, noted Cecil Smith, operations manager at United Rentals in Edmonton, Alberta, Canada. In the summer, fuel manufacturers mix in additives to prevent gas and diesel from evaporating in the heat.

But winter fuel needs to withstand cold temperatures — so if you have your own fuel storage tank, don’t use leftover summer fuel in winter.

Thanks to the moisture content in diesel as well as the wax diesel contains, in winter diesel turns into a gel-like substance too thick to make its way through the fuel lines, explained Eric Jarvis, regional project development manager at United Rentals in Detroit, Michigan.

Gelling doesn't cause immediate damage to the machine, said Smith, “but it can cause extra wear and tear to the fuel pump."

Running the equipment or heating the engine block before use will thin out the fuel, but if the machine sits in the yard too long, Jarvis noted, the thickened diesel will prevent the machine from starting.

A winter fuel blend can keep that from happening.

Just like all winter-blend formulas, the Shell product United Rentals uses in the northern Alberta area has additives that prevent the fuel from thickening in the winter cold, Smith noted. Shell starts blending for winter in October and stops including cold-weather additives in May, he said.  The only potential change for the operator after the mix changes for winter is a slight drop in fuel economy.

The perfect winter blend depends on how deep the freeze is, but a common ingredient is kerosene. "Kerosene has a much [lower] freezing point," Jarvis said. However, he added, operators should be aware that a mix too high in kerosene can dry out gaskets and cause fuel leaks.

Gasoline doesn’t set up like diesel but can be prone to freezing, so there is also a winter blend of gasoline.

The good news is that fuel manufacturers do the work of changing the blend for you as the seasons change, giving you one less thing to worry about.