What is DEF Freeze?

March 12, 2020

Trucker's Corner

At Trucker’s Corner, you can navigate to topics regarding the trucking industry, lifestyle while on the road, and truck health. International Used Trucks has the information you need to keep you on the Road to Revenue

As the temperatures grow colder around and , you might hear talk of winter truck maintenance and your DEF freezing point. What is DEF freeze and how does it affect your driving? DEF, or your Diesel Exhaust Fluid, transforms harmful nitrous oxide emissions into water and gas – which keeps your vehicle under federal guidelines. And while this fluid can handle quite a range of temperatures, the chilly winters of can stop it in its tracks. Take a look at Diesel Exhaust Fluid and the DEF freezing point below:

How Is DEF Made?

Diesel Exhaust Fluid is a blend of aqueous urea, consisting of 32.5% high purity urea and 67.5% deionized water. This precise formula is necessary for your SCR system, so it’s important to look for certified DEF products. Look for certifications like:

  • The American Petroleum Institute (API)
  • German Institute of Standardization DIN70700
  • The International Organization for Standardization ISO 22241-1
  • AUS – 32 Specifications

What Temp Does DEF Freeze?

If your Diesel Exhaust Fluid is made with the recommended 32.5% urea concentration, you’ll get the lowest possible DEF freezing point of 12 degrees Fahrenheit or -11 degrees Celsius. In a quality DEF product, the water and urea within the DEF product will freeze and thaw at the same rate – which maintains the integrity of the product. In poorly mixed formulas, the water may thaw sooner to create a diluted mix or the urea may thaw sooner to form and concentrated mix. Both can cause problems for your vehicle.

How Can I Prevent DEF Freeze?

Your SCR system will provide heat to your DEF tank and supply lines, which will thaw the fluid automatically. Here are a few other tips to keep in mind:

  • Do not add anti-gelling or freeze point improver to the mix. This can damage your SCR components and degrade your DEF.
  • Be sure to store your DEF in a cool, dry, well-ventilated area that is out of direct sunlight. This will ensure the highest quality product.
  • Keep an eye on the expiration date of your DEF. Over time, the product will break down and work less effectively.

Find Out More About DEF and SCR with International Used Truck Center

Now that you can answer, “What is DEF freeze?” and, “What temp does DEF freeze?”, but if you still have questions about your truck’s inner workings, feel free to contact us at International Used Truck Center. We’re happy to help you with any auto concerns in the area, including sharing our winter driving tips, so don’t hesitate to stop by!

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International Used Truck Center 41.776180, -88.200918.