DEF Shelf Life and Temperature Requirements

All About DEF

Why Your Vehicle Needs It, Where to Find It, and Correct Temperature Control Storage

DEF – short for Diesel Exhaust Fluid – is a major component of diesel-run vehicles these days. Whether you’re a fleet manager, provide wholesale supplies to transportation companies, or drive a diesel engine vehicle, your understanding of DEF is essential to successful usage of this EPA-required product. Learn (or review) exactly how it works, why it’s so important, and how to store it for optimal performance and extended DEF fluid shelf life. Let’s get started.

Emissions Issues Before DEF Saved the Day

The introduction of DEF to the scene is actually quite recent. If you’ve been in the business for a while, you probably remember the days before DEF was required. In fact, a short eight years ago, diesel-run vehicles were cruising all over the freeways of America with abandon, projecting trails of harmful emissions in their wake. Certain manufacturers even purposefully covered up the amount of harm being done by switching off the emissions controls while driving. No good, right?

But in the late 1990’s, the day of reckoning came. The EPA (Environmental Protection Agency) penalized leading trucking manufacturers with heavy fines to fix the alarming pollution problem. One such leading company was Cummins, which promised to invest the required amount of effort and funds into cleaning up the pollution situation. The next decade was dedicated to finding a healthier exhaust emissions solution.

The solution was finally solidified in 2011, when all diesel vehicles began to be manufactured with a DEF tank. DEF was now 100% required.

DEF Fluid Shelf Life Chart

def fluid shelf life


What is DEF?

DEF is a very simple solution:

  • Two-thirds deionized water
  • One-third urea. 

Urea. Now that’s a word that sounds uncomfortably like another word referring to bodily functions, doesn’t it? Before you squirm too much in your chair, let’s clear something up. Yes, Urea does in fact refer to urine.  (And before you get too freaked out, while urea does in fact refer to urine, it is synthetically made and generally not taken from animals. Phew!) 

The purpose of DEF fluid is to break down the harmful nitrogen oxide emissions that diesel vehicles release. 

Here is a simple breakdown of how DEF works in a diesel engine:

  • The exhaust fluid is pumped into the DEF tank and ready to use when the engine turns on.
  • As the diesel engine runs, DEF is sprayed through the Selective Catalytic Reduction system (otherwise known as the SCR).
  • The fluid is sprayed directly from the catalytic reduction system into the exhaust stream. It never enters the diesel fuel itself. 
  • The ammonia content in the fluid effectively reduces the exhaust to simple nitrogen and water – a much safer emissions option!

Where Can I Purchase DEF?

There are various options for those who work directly with diesel exhaust fluid. The best option will depend on how much you need and your specific uses for the product. 

Here are some options on where to find DEF.

  • Local Hardware Store: If you need a small amount, you can find DEF at the local hardware store or even Walmart.
  • Pump Stations: DEF can be found at most truck stops and even at many retail gas stations. Simply do a google search to find the one nearest you while on the road, or do a little upfront research to ensure your fleet drivers have easy access while on the road.
  • DEF Manufacturer: If you choose to purchase a large amount of DEF and store it for easy and immediate access for your fleet, there are several options available online.

Because of the constant need for high-quality DEF in your vehicle’s SCR system, having more on-hand definitely is a good way to go in most cases for mass freight transportation. 

What Happens If My DEF Tank Is Empty and Not Promptly Refilled?

Just a friendly word to the wise on this one: Don’t let your DEF tank get to empty. When your levels are low, a warning will appear on the dashboard. If the warning goes ignored and the DEF runs out, you’ll find your engine loses quite a bit of power and soon stop altogether, as if you ran out of gasoline. The EPA wasn’t messing around, and the technology put into place to keep the DEF running in your vehicle proves that! 

The last thing any transportation company needs is to have a truck stranded on the side of the road while precious deadlines creep up and are possibly even missed. Make sure you have DEF on hand or know exactly where you can fill up next. 

How Often Should I Fill Up on DEF?

A simple ratio to keep in mind is that of 50:1. For every 50 gallons of diesel fuel your engine uses, it will require 1 gallon of DEF fluid, about 2% of the amount used. 

What Is the Fluid Shelf Life of DEF?

Careful storage is the key component in extending DEF’s shelf life.

  • Store in quality bulk storage containers that are out of direct sunlight
  • Store in a cool, dry, ventilated area
  • Store in temperatures between 12 – 65 degrees Fahrenheit. 
  • Abide by proper handling and dispensing operations to ensure that no contaminants enter the DEF, which could compromise the quality (and ultimately harm your SCR system if it enters the vehicle.)

DEF shelf life is reduced when temperatures are not properly regulated and reach above 86 degrees Fahrenheit. This can cause the DEF to decompose, making it unusable or even harm your vehicle. Temperature temperatures are best when it comes to extending the life of your DEF supply.

What Is the Easiest Way to Extend the Shelf Life of My DEF Supply?

The best, easiest way to extend your DEF’s lifespan is through an effective temperature control system. When it comes to protecting your DEF storage, having the correct equipment in place makes the process frictionless. Here at Powerblanket, we offer just that type of equipment suited for the job in the form or our high-quality line of DEF Storage Heaters. These heaters are specifically created to protect the specific needs of the DEF fluid. 

Our DEF tank heaters offer freeze protection, and even more importantly, keep the DEF from overheating by maintaining a constant ideal temperature to protect your product. 

Why choose Powerblanket for your DEF heating solutions?

  • The rugged vinyl shell effectively protects against freezing
  • Enclose the entire DEF storage container
  • Top flap for easy access 
  • Safety certified
  • Easy to install and manage

Here at Powerblanket, we know how important it is to keep diesel vehicles on the roads, delivering the time-sensitive agriculture products that feed countless families every day. Protecting your vehicles, and the DEF inside of them, simply does not get easier and more effective than Powerblanket’s agriculture heating solutions

Contact Powerblanket Today

Ready to protect and preserve your DEF supply? Contact Powerblanket’s friendly, knowledgeable staff today with any questions you have about protecting your DEF. You can easily reach us at 866.945.4203.

The Powerblanket DEF tank heater is the most efficient and effective way to heat and store diesel exhaust fluid.


Shelby Thompson

Shelby Thompson is the head of standard product sales for Powerblanket. He has a distinguished military career, having served in both Afghanistan and Iraq. In his time in the Marines, Shelby acquired an impressive skillset that he now uses in his current role. When he's not working, Shelby loves spending time outdoors with his wife, son, and daughter. He is also a semi-keen hunter, fair weather fisherman, and shooter. Unfortunately, Shelby also has something of an unlucky streak when it comes to Fantasy Football at the company.

3 thoughts on “DEF Shelf Life and Temperature Requirements

  1. I have a customer that just purchased a fleet of 2012 diesels and will be very cold weather this winter. My question to you is, is there a smaller blanket that you can put on the tank on your truck? I am assuming that it would work like a battery warmer blanket. PLease let me know. Im in Wyoming and I think there are alot of people with intrest in this. thank you

  2. Hi i Have a 2012 Ford F 450 truck which requires add blue,i live in Australia where it can be very hot and i have changed the heater in the tank at 20000 klm and now at 54000 klm it says the heater needs to be changed again my question is do i have to change the heater as i live in an area where temp ranges from 25c to 40c are these heaters set up for very cold climates my ,truck is running normal at the moment.

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