Mercedes-Benz R-Class 2012 Owners Manual - Manual (Page 164)

use a sponge and cold water to clean it. DEF
residues crystallize after time and
contaminate the affected surfaces.
! DEF is not a fuel additive and must not be
added to the fuel tank. If DEF is added to
the fuel tank, this can lead to engine
damage.
i If you are adding between maintenance
intervals, add approximately 1 gallon (3.8 l)
of DEF to the DEF tank. One gallon (3.8 l)
of DEF is approximately 2 DEF refill bottles.
For further information on DEF, see:
(
Y page 357).
The DEF filler neck is under the cargo
compartment floor.
X Switch off the ignition.
X Open the tailgate.
X Lift up the trunk floor ( Y page 296).
X Remove lug wrench ; and ratchet wrench
= if applicable.
X Turn DEF cap : counter-clockwise and
remove it.
X Turn DEF filler cap ? counter-clockwise
and open it.
Filler cap ? is secured with a plastic strap.
X Unscrew the covering cap from DEF refill
bottle A.
X Place DEF refill bottle A on the filler neck
as shown and screw on clockwise hand-
tight.
! Only screw on the DEF refill bottle hand-
tight. It could otherwise be damaged.
X Press DEF refill bottle A down.
The DEF tank is filled. This may take up to
one minute.
i If the DEF refill bottle is no longer pressed
down, the filling process stops and the
partially emptied bottle can be removed.
X Release DEF refill bottle A.
X Turn DEF refill bottle A counter-clockwise
and remove it.
X Place DEF filler cap ? on the filler neck and
turn it clockwise.
162
Refueling
Driving and parking