Diesel Exhaust Fluid (DEF) is an essential component for modern diesel engines, helping reduce emissions and keep fleets compliant with EPA standards. However, crystallization is a common issue that can cause major headaches for fleet operators, mechanics, and site managers. If left unaddressed, DEF crystallization can lead to clogged pumps, injectors, and filters, resulting in costly downtime and repairs.
What Causes DEF Crystallization?
DEF is made of 32.5% urea and 67.5% deionized water. Under normal conditions, it remains a clear, stable solution. However, a few factors can lead to crystal buildup inside DEF storage tanks and dispensing systems:
Exposure to Air – When DEF comes into contact with air for extended periods, water in the solution evaporates, leaving behind urea crystals.
Temperature Fluctuations – DEF freezes at 12°F (-11°C), and repeated freezing/thawing cycles can contribute to crystallization.
Long-Term Storage – DEF has a shelf life of up to two years, but when stored improperly or left unused, it can degrade and form crystals.
Contaminants – Dirt, dust, and even small amounts of fuel or oil can react with DEF, leading to crystal deposits.
Why Is DEF Crystallization a Problem?
Crystallized DEF can clog injection systems, filters, and pumps, restricting fluid flow and leading to faulty SCR (Selective Catalytic Reduction) system performance. This can cause:
Vehicle warning lights and error codes
Reduced engine performance
Higher emissions and non-compliance with EPA standards
Costly repairs and downtime
How to Prevent DEF Crystallization
The good news is that proper storage and handling can minimize DEF crystallization issues. Here’s how:
✅ Keep DEF tanks sealed – Reducing exposure to air prevents evaporation and buildup.
✅ Store DEF at stable temperatures – Keep storage between 12°F and 86°F to maintain fluid integrity.
✅ Use DEF within recommended timeframes – Avoid keeping DEF in storage longer than two years.
✅ Regular tank inspections – Checking for buildup and flushing tanks periodically can help prevent clogs.
✅ Use high-quality DEF – Low-quality or contaminated DEF is more likely to cause buildup. Always source from trusted suppliers like DEF Dealers.
Solutions for DEF Crystallization
If you’re already dealing with DEF buildup, here’s how you can clear it up:
🔹 Flush the system – A full system flush with fresh DEF can help dissolve minor crystallization.
🔹 Manual cleaning – In severe cases, crystallized DEF may need to be manually removed from tanks, filters, or pumps.
🔹 Use proper DEF additives – Some specialized solutions can help break down minor crystal formations safely.
Need High-Quality DEF Delivered? We’ve Got You Covered.
At DEF Dealers, we provide fresh, high-quality DEF to job sites, fleets, and facilities nationwide. Keeping your DEF clean and contaminant-free is key to preventing costly breakdowns and keeping your fleet running efficiently.
🚛 Looking for bulk DEF delivery? Contact us today!
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