DEF
Important safety notes
Comply with the important safety notes for service products when handling DEF .
DEF is a water-soluble fluid for the exhaust gas aftertreatment of diesel engines. It is: • not poisonous • colorless and odorless • not flammable When you open the DEF container, small amounts of ammonia vapor may be released
Ammonia vapors have a pungent odor and are particularly irritating to the skin, to mucous membranes and to the eyes. You may experience a burning sensation in your eyes, nose and throat. Coughing and watering of the eyes are possible.
Do not inhale ammonia vapors. Fill the DEF tank only in well-ventilated areas.
Low outside temperatures
DEF freezes at a temperature of
approximately 12 
(-11
). The vehicle is
delivered from the factory equipped with a
DEF preheating system. Winter operation can
thus be guaranteed even at temperatures
below 12 
(-11
).
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
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
Filling capacities
See also:
Important safety notes
WARNING
If flammable materials such as leaves, grass
or twigs are exposed to prolonged contact to
parts of the exhaust system that heat up, they
could ignite. There is a risk of fire.
Park the ...
Coolant
Important safety notes
WARNING
If antifreeze comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Let the engine cool down before ...
Problems with the transmission
Transfer case
Performance tests may only be carried
out on a 2-axle dynamometer. The brake
system or transfer case could otherwise be
damaged. Contact a qualified specialist
workshop for a perf ...