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Can we call it a DEF jam? Everything is in short supply as supply chains continue to unlink. The latest commodity reportedly hit is DEF, or the blue diesel exhaust fluid that every diesel sold in the U.S. after 2010 needs to cut emissions. This means that every diesel truck, diesel RV, SUV, and car owner will likely have to look harder, and pay more for, DEF. A diesel engine can technically run without DEF, but your diesel vehicle likely won’t let you start it if the DEF tank is empty.

What is DEF?

The U.S. is facing a looming DEF shortage that could make driving a diesel very expensive.
A tube going into a tank nozzle for AdBlue, with a tank cap for diesel on the right, on a Skoda Kodiak pictured in Goettingen, Germany, 31 July 2017. Photo: Swen Pförtner/dpa (Photo by Swen Pförtner/picture alliance via Getty Images)

Diesel exhaust fluid is the blue stuff you have to add to any diesel sold in the U.S. after 2010. To combat diesel emissions modern diesel engines use an additive to clean up their emissions. Mercedes-Benz, for example, calls its cleaner diesels BlueTEC. Benz uses AdBlue, which is a brand name for urea. Diesels use urea fluid in their catalytic converters to convert toxic nitrogen oxide to simple nitrogen and water. Most gas stations sell DEF, or Diesel Exhaust Fluid, which is about $15 for 2.5 gallons and needs to be filled about every fourth fill-up.

Why could there be a DEF shortage?

Closeup of a Cummins turbo diesel badge on the fender of a Ram pickup truck.
2022 Ram with a Cummins engine | Stellantis

A major portion of our urea comes from Europe, and because of the war in Ukraine we’re seeing a shortage of it, according to Newsweek. Russia is one of the world’s major exporters of it. China, too, is a major exporter of it, and it has suspended exports. Weather, too, has caused supply chain disruptions. Since it’s also a major component in fertilizers, there’s intense competition for urea.  Truck stops, however, say they’re not seeing any shortages, according to CCJ.

There is no urine in DEF

The urea in DEF comes from fertilizer, not urine. Internet rumors of pig or bat urine being processed for DEF are untrue. Most animal urine is less than 5% urea, while DEF is 32.5% urea. So, don’t pee in the DEF tank and think it’ll work.

A DEF shortage would be the next calamity to hit trucking

Semi trucks are need a lot of DEF, and a DEF shortage could cause prices for trucking to skyrocket.
Semi-truck | Sander Yigin via Unsplash

Fuel, and especially diesel fuel costs have gone up in the last year. DEF prices are now going up, too, and will likely affect costs. While those of us with regular diesel cars and trucks usually buy a 2.5-gallon bottle for about $15 to $20, truckers usually buy it by the drum or buy it by the gallon from a pump right at the truck stop. Today, those drums are nearing $300.

How should you store DEF?

A bottle of def could get more expensive if the US sees a major DEF shortage.
A bottle of DEF | Greenchem adblue4you Wikimedia Commons

How do you know if your DEF is still good? DEF has a shelf life of two years, but that is temperature-dependent. The cartons are also light-tight because direct sunlight can corrupt DEF. Companies that make DEF, like SC Lubricants, say that higher temperatures will make it degrade more quickly. It should also not be stored below 12 degrees. Also, don’t store it in metal because it corrodes many common metals like steel, copper, and aluminum.


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