DEF
Important safety notes Comply with the important safety notes for
service products when handlin gDEF
(Y page 365).
DEF is a water-soluble fluid for the exhaust
gas aftertreatment of diesel engines. It is:
R not poisonous
R colorless and odorless
R not flammable
When you open the DEF container, small
amounts of ammonia vapo rmay be released.
Ammonia vapors have a pungen todor 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 vehicl eis
delivered from the factory equipped with a
DEFp reheating 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:
R increased emission values
R damage to the catalytic converter R
engine damage
R malfunctions in the BlueTEC exhaust gas
aftertreatment system
Assuring the purity of DEF is particularly
important with respect to avoiding
malfunctions in the BlueTEC 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.
Filling capacities Model Total capacity
GLK 250 BlueTEC
7.3 US gal
(27.5 l) Engine oil
General notes !
Never use engine oil or an oil filter of a
specificatio nothe rthan is necessary to
fulfill the prescribed service intervals. Do
not change the engine oil or oil filter in
order to achieve longer replacement
intervals than those prescribed. You could
otherwise cause engine damage or damage
to the exhaust gas aftertreatment.
Follow the instructions in the service
interval display regarding the oil change.
Otherwise, you may damage the engine and
the exhaust gas aftertreatment.
When handling engine oil, observe the
important safety notes on service products
(Y page 365).
The engine oils are matched to the
performance of Mercedes-Benz engines and
service intervals. You should therefore only
use engine oils and oil filters that are
approved for vehicles with maintenance
systems.
For a list of approved engine oils and oil filters,
consult an authorized Mercedes-Benz Service products and fillingc
apacities
369Technical data Z
