How to Keep Your DEF Tanks From Freezing

Preventing your DEF tanks and totes from freezing is actually very easy: just add heat. Read this post to learn how to most effectively warm your DEF tanks this winter season.

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To keep your DEF tanks from freezing, consider Heat Authority tote warmers and heaters that maintain the correct temperature for your sensitive materials.

DEF vs Cold Weather

AdBlue DEF is essential for the trucking industry, as nearly all trucks run on diesel fuel. DEF allows trucks to stay on the road during the winter while reducing harmful emissions from diesel engines. If the weather gets too cold, however, it can freeze DEF stored in tanks into a solid block of unusable ice.

DEF can be kept at a usable temperature in storage tanks on the truck or in large DEF totes at a work site. Doing so requires heating equipment to make sure any DEF you have stored will not freeze, such as tote heaters. Knowing what kind of tote heater technology to use will help you find the most affordable, quality solution to prevent your DEF tanks from freezing. But first, let’s make sure you have a clear understanding of what DEF is.

What is DEF? What is DEF used for?

DEF is an acronym for Diesel Exhaust Fluid. It’s a water-based solution that is injected into the exhaust stream of a diesel engine to reduce emissions of nitrogen oxides. AdBlue DEF is typically made up of 32.5% urea and 67.5% water (deionized). It is stored in a separate vehicle tank and injected into the exhaust stream via a DEF dosing unit. The DEF reacts with the NOx in the exhaust as part of the Selective Catalytic Reduction (SCR) system to form harmless nitrogen gas and water vapor.

Other things to know about DEF

Diesel exhaust fluid is a clear, odorless liquid that can be mistaken for water. When dried, DEF takes the form of small, white crystals. Make sure your DEF tanks are clearly labeled so no one accidentally mistakes your DEF tank as water storage.

Man holding a solid DEF crystal in his hand.

Another thing about DEF to understand is that there is no substitute for it. The water-based solution that makes up DEF is made up in part of synthetic urea. Urea is part of what makes up urine. However, do not under any circumstance urinate into your DEF storage tank to keep it warm. Synthetic urea is vastly different from naturally-occurring urea. Peeing into the DEF tank will ruin your DEF and lead to expensive repair costs. It sounds ridiculous, but people have done it.

Additionally, DEF has no significant impact on fuel economy. However, using frozen DEF will slow down your engine and use up more diesel fuel. More on that below.

Why is it important to keep your DEF tanks from freezing?

When a DEF tank freezes, the water in the solution can turn to ice and damage the tank. The ice can also block the nozzle on the dosing unit, preventing the DEF from being injected into the exhaust stream. This can cause a reduction in engine performance and an increase in emissions.

What temperature does DEF freeze?

DEF freezes at 11-12°F. While this is well below the freezing point of water, frozen DEF is a massive pain to work with and should be avoided at all costs.

What happens if my DEF freezes in my truck?

When DEF can’t make it into the engine, either because it has frozen in its tank or because you’ve run out of it, you’re in big trouble. Engines have sensors in place to know when DEF isn’t getting to where it needs to be. Once the sensors have picked up on a lack of DEF getting to the engine, a warning light will appear that looks like this:

This light will stay on until you unblock the ice from the nozzle or refill the tank. While it’s on, your engine will slow down dramatically, preventing you from doing anything other than creeping along to the nearest gas station.

Is DEF still good if it freezes?

AdBlue DEF is safe to use no matter how many times it has frozen and thawed. If your tank or tote has frozen, you can always warm it up and use it again.

What are different methods to keep your DEF from freezing?

Keep it warm. Most companies will recommend using a tote heater. Tote heaters provide evenly-spread heat across each surface of the DEF storage tote, preventing DEF from getting too cold. Using a tote heater or tote warmer will ensure your DEF stays in a liquid form, ready to use when you need it.

DEF tote heaters vs engine block heating

Does the engine block heater prevent DEF from freezing? Technically yes, but this only works while the engine is operating. DEF will freeze in tanks or storage totes without a consistent heat source. This is why tote heaters are so important!

Prevent DEF from Freezing with Heat Authority

Frozen DEF is no joke. Understanding tote heaters will help prevent your DEF tanks from freezing and make sure you stay on the road.