For fleets running modern diesels, diesel exhaust fluid is a routine consumable, but poor DEF management causes derates that take trucks out of service.
Buy and store DEF correctly
DEF degrades with heat and time and has a shelf life. Store it cool, sealed, and rotate stock so you always use fresh fluid. Bulk storage needs temperature control and clean dispensing.
Prevent quality-related derates
Poor-quality or contaminated DEF triggers faults and derates. Use quality fluid, keep dispensing equipment clean, and never let a tank run empty, which forces a derate.
- Rotate DEF stock, first in first out
- Keep dispensing nozzles and containers clean
- Never let a truck's DEF tank run empty
- Address NOx sensor and dosing faults promptly
Track consumption
Monitor DEF usage per truck; a sudden change can signal a dosing or sensor problem worth investigating before it becomes a derate.
Frequently asked questions
How should a fleet store DEF?
Cool, sealed, and rotated first-in-first-out, since DEF degrades with heat and time and has a shelf life.
What causes DEF-related derates?
Poor-quality or contaminated fluid, an empty tank, or dosing and NOx sensor faults. All take trucks out of service.
Should I track DEF consumption?
Yes. A sudden change per truck can signal a dosing or sensor problem to catch before a derate.
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