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DEF Tips and Tricks

By Glen Sokolis, Contributor

Fleet companies are facing all kinds of new decisions with diesel exhaust fluid, which came into play with the Environmental Protection Agency’s 2010 emissions standards. DEF is used to treat the exhaust of the engines running selective catalytic reduction (SCR) technology to meet the requirements. All but one engine maker use SCR.

This created a new industry, the DEF market. It started off slow, but today experts believe industry growth will double from last year, to 150 million gallons in 2012. Major truckstops are installing tanks and pumps like there’s no tomorrow, because as every old truck is retired to the truck graveyard, a new truck is put into use that most likely needs DEF.

So now fleets might have one truck out of 40 that needs DEF, but that one truck might not get anywhere close to a truckstop that sells DEF. So they are faced with buying it in 2-1/2 gallon jugs, 55-gallon drums, 330-gallon totes or even putting in their own tank system.

Here are a few areas where we’ve seen questions and concerns with our clients:

DEF Creep

If your drum or tote pumps or fittings look like they were snowed on last night, you’re experiencing “DEF creep.” The white, powdery substance is the crystallization of urea left behind from DEF evaporation.

For example, after dispensing DEF out of your tote, the hose is left with a residual coating of product. The air will evaporate the water, and urea crystals will begin to build a chain. This will typically happen in about 30 minutes. The crystals will find even the smallest path through connections, especially threaded connections and seal areas.

How do you prevent “DEF creep”? Make sure all fittings that come in contact with DEF are tight and proper seals are used. Try minimizing breaking connections and wipe down any urea crystallization as soon as it forms.

Water can be used to easily wash off urea that has crept onto the truck, tank or dispensing equipment.


DEF is a whole new frontier, creating lots of questions for fleet owners. I had one CFO ask me if his fuel company was trying to pull a fast one on him about needing DEF. I had to explain to him that they weren’t and, like it or not, all of his trucks likely would soon be running DEF.

We have found fleet owners are concerned with their drivers pumping the wrong product into the wrong tank. It appears, for the most part, that DEF tanks have a magnetic interface with the spout of DEF nozzles. What this means is if a driver tries to put the DEF nozzle in the diesel fuel tank, which does not have a magnetic mis-filling adapter, then no DEF will be released.

A few things to consider for extra precaution when using DEF:

– Use dedicated equipment for DEF for dispensing and storing. Don’t use funnels or bottles from other products.
– Protect the DEF from fuel, oil, water, grease or anything else except DEF.
– Store DEF between something above 32 degrees and 86 degrees and not in direct sunlight. With this your shelf life should be a solid 12 months.

Before you install a tank, I would strongly recommend to any company to get a solid feel of how much DEF you need today on a daily basis and what you will need in a few years. You don’t want to install a 2,000-gallon DEF tank today to realize two years from now you need that tank filled up daily or more often.

Demand and pricing

The pricing for DEF has been all over the board, from $1.80 in bulk to $10 in packages per gallon. The demand has not yet caught up with supply, and that is about to change as the industry doubles in volume this year and I would assume double in volume again next year as new trucks are brought onto market. Since DEF is made from 32.5% urea and the rest purified water, I would not expect any major shortages or price gouging anytime soon, although urea is a product used worldwide and can at times get caught in some volatility.

As a fleet manager all of this extra work could drive you nuts, but look at the bright side: Most fleets find SCR has a performance advantage and has shown an increase of 3-5% in fuel efficiency. At $4 to $5 a gallon for diesel, that’s a pretty good deal.

Glen Sokolis is founder and president of Sokolis Group, Warrington, Pa., a fuel management and consulting company.

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