coolant reservoir MERCEDES-BENZ S-Class 2011 W221 Owner's Manual

much oil has been added. This can lead to
damage to the engine or the catalytic
converter. Have excess oil siphoned off.
Further information on engine oil
(Y page 513).
XReplace cap : on the filler neck and
tighten clockwise.
Ensure that the cap locks into place
securely.
Checking and adding other service
products
Check coolant level
Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
XTurn the key to position 2 (Y page 299) in
the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 299).
XCheck the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
158 ‡ (70 †).
GWarning
In order to avoid any potentially serious burns:
Ruse extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system, or
if the coolant temperature display indicates
that the coolant is overheated.
Rdo not remove the pressure cap on the
coolant reservoir if the coolant temperature
is above 158 ‡ (70 †). Allow the engine to
cool down before removing the cap. The
coolant reservoir contains hot fluid and is
under pressure.
Rusing a rag, slowly turn the cap
approximately 1/2 turn to relieve excess
pressure. If opened immediately, scalding
hot fluid and steam will be blown out under
pressure.
Rdo not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts.
XSlowly turn cap : half a turn counter-
clockwise and allow excess pressure to
escape.
XTurn cap : further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
= in the filler neck when cold, there is
enough coolant in coolant expansion
tank ;.
If the coolant is approximately 0.6 in
(1.5 cm) above marker bar = in the filler
neck when warm, there is enough coolant
in coolant expansion tank ;.
XIf necessary, add coolant that has been
tested and approved by Mercedes-Benz.
XReplace cap : and turn it clockwise as far
as it will go.
For further information on coolant, see
(Y page 515).
Windshield washer system/headlamp
cleaning system
The washer fluid reservoir is used for both the
windshield washer system and the headlamp
cleaning system.
450Engine compartmentMaintenance and care