Diesel Exhaust Fluid (DEF) plays a crucial role in reducing harmful emissions from diesel engines. However, like any fluid, it reacts to extreme temperatures, and freezing can become a concern during colder months. Understanding how DEF behaves in freezing conditions and how to manage it effectively can help you avoid costly issues and maintain your vehicle's performance.
Here’s everything you need to know about DEF and freezing temperatures.
Why Does DEF Freeze?
DEF is a mixture of 67.5% deionized water and 32.5% urea. This specific ratio ensures that DEF complies with industry standards for emission reduction. However, because it contains a high percentage of water, DEF begins to freeze at 12°F (-11°C). When it freezes, DEF expands, just like water, which can potentially damage storage containers or system components if not handled properly.
Will Freezing Harm the Quality of DEF?
The good news is that freezing does not degrade DEF’s quality. Once the fluid thaws, it retains its original properties and effectiveness. The urea and water solution naturally re-blends as it melts, so there’s no need to worry about separation or performance issues.
How Does Freezing Affect Vehicles with DEF Systems?
Modern diesel engines with DEF systems are designed to handle freezing temperatures. Here’s how they work:
Built-in heaters: Most DEF tanks are equipped with heating systems that thaw the fluid as the engine operates.
Startup safety: Vehicles are programmed to operate normally during startup, even if the DEF is frozen, as long as the system is functional. The DEF will thaw gradually as the engine warms up.
Tips for Managing DEF in Cold Weather
To avoid potential issues with frozen DEF, follow these best practices:
1. Store DEF Properly
Temperature control: Store DEF in a location where temperatures remain above 12°F, such as a heated garage or insulated shed.
Avoid direct sunlight: While preventing freezing is important, prolonged exposure to high heat can also degrade DEF. Aim for a storage temperature between 32°F and 77°F.
Use proper containers: Always store DEF in approved, sealed containers to prevent contamination and maintain quality.
2. Inspect Your Vehicle’s DEF System
Check heaters: Ensure the DEF tank heater and lines are functioning properly before winter sets in.
Monitor fluid levels: Keep your DEF tank adequately filled to avoid air gaps that can freeze more quickly.
3. Warm Up Before Long Trips
Allow your vehicle to run for a few minutes before driving long distances in extremely cold conditions. This ensures the DEF system warms up and starts working efficiently.
4. Carry Extra DEF
If you’re traveling through areas with freezing temperatures, bring additional DEF in case you need to refill. Ensure the extra DEF is stored in a temperature-controlled environment.
What Happens If DEF Freezes in Storage?
If DEF freezes in its storage container, don’t panic. Follow these steps:
Move to a warmer location: Place the container in a heated area above 12°F to thaw naturally. Avoid using open flames or high-intensity heaters to speed up the process.
Check for expansion damage: Inspect the container for cracks or leaks caused by expansion during freezing.
Stir or shake gently: Once thawed, gently agitate the container to ensure the solution is evenly mixed.
Long-Term Solutions for DEF Storage
For fleets or heavy-duty operations, investing in insulated or temperature-controlled DEF storage solutions can save time and money in the long run. Many suppliers offer heated storage tanks and dispensers specifically designed for cold climates.
Freezing temperatures can pose challenges for managing Diesel Exhaust Fluid, but with proper storage, maintenance, and preparation, these challenges are easily overcome. Understanding how DEF reacts to cold weather and taking proactive steps to protect your system will ensure uninterrupted performance and compliance with emission standards throughout the winter.
By staying informed and prepared, you can keep your diesel engine running smoothly, no matter how low the temperature drops.