Mercedes-Benz 2009 S-Class Operator's Manual page 450

Operation
Engine compartment
Coolant level
The engine coolant is a mixture of water and
anticorrosion/antifreeze.
When checking the coolant level, the vehicle
must be parked on level ground, and the
coolant temperature must be below 158‡
(70†).
G Warning!
In order to avoid any potentially serious
burns:
Use extreme caution when opening the
R
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge
indicates that the coolant is overheated.
Do not remove pressure cap on coolant
R
reservoir if coolant temperature is above
158‡ (70†). Allow engine to cool down
before removing cap. The coolant
reservoir contains hot fluid and is under
pressure.
Using a rag, slowly open the cap
R
1
approximately / turn to relieve excess
2
pressure. If opened immediately,
448
scalding hot fluid and steam will be blown
out under pressure.
Do not spill antifreeze on hot engine
R
parts. Antifreeze contains ethylene
glycol which may burn if it comes into
contact with hot engine parts.
S 550 (example illustration)
Cap
1
Coolant expansion tank
2
Marking bar in the expansion tank
3
X
Using a rag, turn cap slowly
1
1
approximately / turn counterclockwise
2
to release any excess pressure.
X
Continue turning cap counterclockwise
1
and remove it.
The coolant level is correct if the level
for cold coolant: reaches marking bar
R
in coolant expansion tank
3
for warm coolant: is approximately 0.6 in
R
(1.5 cm) higher
X
Add coolant as required.
X
Replace and tighten cap 1.
For more information on coolant, see the
"Technical data" section ( Y page 605) and
( Y page 609).
Washer system and headlamp
cleaning system
G Warning!
Washer solvent/antifreeze is highly
flammable. Do not spill washer solvent/
antifreeze on hot engine parts, because it
may ignite and burn. You could be seriously
burned.
! Always use washer solvent/antifreeze
where temperatures may fall below
freezing point. Failure to do so could result
in damage to the washer system/fluid
reservoir.
2