Diesel Exhaust Fluid Explained
What is DEF?
Diesel Exhaust Fluid (DEF) is a solution made up of 67.5% deionized water and 32.5% high purity urea. It plays a critical role in reducing harmful emissions produced by diesel engines.
DEF is injected into the exhaust stream of diesel vehicles. When introduced, it breaks down and vaporizes, converting harmful nitrogen oxide (NOx) emissions into harmless nitrogen and water vapor. This process is known as Selective Catalytic Reduction (SCR): a technology essential for meeting the strict emission standards set by the Environmental Protection Agency (EPA).
It’s important to note that DEF is not a fuel additive and never mixes with diesel fuel. It is stored in a completely separate tank in the vehicle. DEF usually freezes at 12°F (-11°C), but DEF tanks are insulated and designed to withstand cold temperatures, ensuring proper operation in various climates.
Why it matters:
- Keeps your fleet compliant with federal emission regulations
- Prevents engine derating and costly downtime
- Supports environmental and sustainability goals
- Protects your equipment investment
How Much DEF Does My Truck Need?
As a general guideline, most trucks use approximately one gallon of DEF for every 200 miles driven. Actual consumption may vary depending on vehicle type, load, and driving conditions.
DEF Best Practices
To ensure optimal performance and product longevity:
- Check DEF levels regularly
- Avoid cross contamination – always keep containers sealed
- Store DEF in a cool, dry place out of direct sunlight
- Be mindful of shelf life: DEF typically lasts up to two years when stored properly
