Mercedes-Benz 2013 S-Class Operator's Manual page 328

Refueling
326
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.
! Only screw on the DEF refill bottle hand-
tight. It could otherwise be damaged.
The filler neck for DEF is located under the
"Minispare" emergency spare wheel in the
trunk floor.
Switch off the ignition.
X
Open the trunk.
X
Lift the trunk floor up (
X
Turn the "Minispare" emergency spare
X
wheel fastening in the direction of the
arrow and remove it.
Remove the "Minispare" emergency spare
X
wheel.
Turn DEF cap : counter-clockwise and
X
remove it.
X
page 442).
Y
X
X
X
i
X
Turn DEF filler cap ; counter-clockwise
and open it.
Filler cap ; is secured with a plastic strap.
Unscrew the covering cap from DEF refill
bottle =.
Place DEF refill bottle = on the filler neck
as shown and screw on clockwise hand-
tight.
Press DEF refill bottle = down.
The DEF tank is filled. This may take up to
one minute.
To add between service intervals, fill the
DEF tank with approximately 1 gal (3.8 l) of
DEF. 1 gal (3.8 l) of DEF is equivalent to
approximately 2 DEF refill bottles. Then
have the DEF supply checked at a qualified
specialist workshop and completely refilled
if necessary.
Release DEF refill bottle =.
Refilling stops when the DEF refill bottle is
no longer pressed down. The DEF refill
bottle can be removed when it has been
only partially emptied.