DEF
Important safety notes
For BlueTEC vehicles only.
DEF is a non-flammable, non-toxic, colorless, odorless and water-soluble fluid.
Rinse surfaces that have come into contact with DEF immediately with water or remove DEF using a damp cloth and cold water. If the DEF has already crystallized, use a sponge and cold water to clean it. DEF residues crystallize after time and contaminate the affected surfaces.
High outside temperatures
If DEF heats up to over 122 °F (50 °C) for extended periods, e.g. as a result of direct sunlight on the DEF reservoir, DEF can decompose. Ammonia vapors develop as a result.
WARNING
When opening the filler cap of the DEF tank
ammonia gas vapors may escape. Refill DEF
in a well ventilated area only. Ammonia gas
vapors have a pungent odor and are
particularly irritating for your skin, mucous
membranes, and eyes. Inhaling ammonia gas
vapors will cause burning eyes, nose, and
throat, as well as coughing and watering eyes.
Low outside temperatures
DEF freezes at a temperature of approximately 12 °F (–11 °C). The vehicle is equipped with a DEF preheating system when it leaves the factory. Winter operation is therefore also guaranteed at temperatures below 12 °F (–11 °C).
Additives
Only use DEF in accordance with ISO 22241. Do not use additives with DEF and do not dilute DEF with water. This may destroy the BlueTEC exhaust gas aftertreatment system.
Purity
Assuring the purity of DEF is particularly important with respect to avoiding malfunctions in the exhaust gas aftertreatment system.
If DEF is pumped out of the DEF tank, e.g.
during repair work, it must not be returned to the tank. The purity of the fluid can no longer be guaranteed.
Impurities in DEF (e.g. due to other service products, cleaning agents or dust) lead to:
- increased emission values
- damage to the catalytic converter
- engine damage
- malfunctions in the BlueTEC exhaust gas
aftertreatment system
See also:
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