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DEF Freezing

As the seasons change and the weather starts to get colder, people begin to focus on protecting things from freezing. They’ll bring their plants inside, cover their pools, and start their cars early in the morning so it will be nice and warm by the time they get in for work. During this season, Diesel Exhaust Fluid (DEF) producers are often asked about DEF freezing. There are always questions about when will freeze and how to prevent DEF from freezing. Read on to learn about DEF freezing and other questions related to the care of DEF!

When Does DEF Freeze?

DEF, comprised of 32.5% urea and 67.5% deionized water, doesn’t have the freezing point of water. The urea mixture has a much lower freezing point of 12 degrees Fahrenheit, which is -11 degrees Celsius. This solution doesn’t break into just urea and just water, either. The solution freezes at the same rate, and also thaws at the same rate. This means that at no point does the DEF freezing cause the solution to become over concentrated or diluted. Since DEF freezing and thawing occurs at the same rate, there is no harm to the product which means that the urea solution is still safe to use if it has been frozen!

Does DEF Freezing Cause Expansion?

Since DEF is a mixture of deionized water and urea, it reacts somewhat like water in that it does expand when frozen. DEF freezing usually causes about a 7% expansion. It is important to note that DEF freezing was taken into account when creating the packaging and tanks that are supposed to hold DEF. DEF packaging and tanks allow for expansion. However, one must be aware of the expansion of DEF when filling.

How to Prevent DEF Freezing?

DEF freezing was taken into account by the OEMs prior to creating the Selective Catalytic Reduction (SCR) systems. Therefore, the SCR systems are designed to provide heating for the DEF tank and supply lines. However, if the vehicle is shut down and is contained in 12 degrees Fahrenheit, then it is likely that the DEF will. Diesel owners do not need to worry about DEF interfering with their vehicle, however. If DEF freezes when the vehicle is shut down, start up and normal operation of the vehicle will not be inhibited. The DEF will be quickly thawed by the SCR heating system in order to return it to liquid form and resume normal operation.

Can Anything Be Added to Prevent DEF Freezing?

Many people want to know if they can add anti-gelling or freeze-point-improver to the DEF mixture in order to prevent it from freezing. Additives should NOT be added to the urea solution because DEF must remain pure. The quality of DEF is extremely important to allowing it to perform correctly. Adding any additives would damage its ability to perform correctly and could even result in damages to the SCR system. No additives are approved at this time for mixing into DEF.

If you have any other questions about DEF freezing, thawing, or ordering, please contact Victory Blue today!