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For School Buses, Snow Plows and Emergency Vehicles, Diesel Fuel Presents a Problem in Frigid Temps

CU Bus (Credit: Frank Miller; Flickr)

When the temperatures get this low, anyone who drives a diesel engine knows they’ve got to be careful. That’s because when diesel fuel gets down to a certain temperature, the paraffin in it starts to harden, or “gel.”  KSMU’s Jennifer Davidson reports on how this is affecting school buses, snow plows and fire engines.

That hardened paraffin substance coats the engine filter and keeps fuel from flowing. In other words, it can shut a vehicle down.

Earlier this afternoon, I was joined on the phone by Gary Shisler from the Missouri Department of Transportation in Springfield. He’s in charge of the MoDOT district garage, which includes about 300 trucks that run on diesel fuel, including snow plows. Shisler says he’s seeing some isolated incidents of this happening in his trucks.

“Most of it has been in our storage tanks themselves,” he said, explaining that the fuel is sometimes so thick it can’t even be pumped into the trucks.

“Anytime a truck’s not running, that’s one less truck out on the highway, not plowing snow…so that does slow our operation down,” Shisler said.

Also, fire trucks and school buses have been affected by the diesel fuel hardening.  Dr. John Mulford is superintendent of the West Plains School district. 

"The concern centers around the safety of the kids. And when you have single-digit or below-zero temperatures, one of the main concerns is buses breaking down and students being stranded with no heat,” Mulford said.

Additives can be added--and are--to help keep the diesel from solidifying. But Mulford said even the additives stop working well at about -5 degrees Farenheit.   The West Plains School District did a test Monday with its buses to see how far they could go in this frigid weather.

“So, what we ran into yesterday as we drove our buses is that the fuel began to gel, and it caused the engine to shut down. And that happened rather quickly after taking the bus off the lot,” Mulford said.

West Plains has already cancelled classes for tomorrow, Wednesday, January 8.

For KSMU News, I'm Jennifer Davidson.