Page 315 of 481

314 OperationEngine compartmentThe coolant expansion tank is located on
the passenger side of the engine compart-
ment.SLK 350 (example)1Coolant expansion tank
2Cap
3Marking bar in the expansion tank
Using a rag, turn cap2 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning cap2 counterclock-
wise and remove it.
The coolant level is correct if the level
for cold coolant: reaches marking
bar3 in expansion tank1
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap2.
For more information on coolant, see
“Coolants” (
page 453).
Battery
Your vehicle’s battery is located in the en-
gine compartment.
The battery should always be sufficiently
charged in order to achieve its rated ser-
vice life. Refer to the Maintenance Booklet
for battery maintenance intervals.
If you use your vehicle mostly for
short-distance trips, you will need to
have the battery charge checked more
frequently.
When replacing the battery, always use
batteries approved by Mercedes-Benz.
If you do not intend to operate your vehicle
for an extended period of time, consult an
authorized Mercedes-Benz Center about
steps you need to observe.
Page 378 of 481

377 Practical hints
What to do if …
Display symbol
Display message
Possible cause/consequence
Possible solution
Ï
Coolant
Stop, engine off
The coolant is too hot.
Stop the vehicle and turn off the engine.
Only start the engine again after the mes-
sage disappears. You could otherwise dam-
age the engine.
/
Coolant
Check level
The coolant level is too low.
Add coolant (
page 313).
If you have to add coolant frequently, have
the cooling system checked by an autho-
rized Mercedes-Benz Center.
Warning!
G
Driving when your engine is badly overheat-
ed can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the hood. Stay away from the engine if you
see or hear steam coming from it. Turn off
the engine, get out of the vehicle and do not
stand near the vehicle until the engine has
cooled down.
The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You can be seriously burned.
!Do not ignore the low engine coolant
level warning. Extended driving with
this message and symbol displayed
may cause serious engine damage not
covered by the Mercedes-Benz Limited
Warranty.
Do not drive without sufficient amount
of coolant in the cooling system. The
engine will overheat, causing major en-
gine damage.
Page 455 of 481

454 Technical dataFuels, coolants, lubricants, etc.Coolant system design and coolant used
determine the replacement interval. The
replacement interval published in the
Maintenance Booklet is only applicable if
MB 325.0 anticorrosion/antifreeze solu-
tion or other Mercedes-Benz approved
products of equal specification (see
Factory Approved Service Products
pamphlet) are used to renew the coolant
concentration or bring it back up to the
proper level.
To provide important corrosion protection,
the solution must be at least 45% anticor-
rosion/antifreeze (equivalent to freeze
protection to approx. -22°F [-30°C]). If you
use a solution that is more than 55% anti-
corrosion/antifreeze (freeze protection to
approx. -49°F [-45°C]), the engine temper-
ature will increase due to the lower heat
transfer capability of the solution. There-
fore, do not use more than this amount of
anticorrosion/antifreeze.If the coolant level is low, water and
MB Anticorrosion/Antifreeze should be
used to bring it up to the proper level (have
cooling system checked for signs of leak-
age). Please make sure the mixture is in
accordance with label instructions.
The water in the cooling system must meet
minimum requirements, which are usually
satisfied by normal drinking water. If you
are not sure about the water quality, con-
sult an authorized Mercedes-Benz Center.Anticorrosion/antifreeze
Your vehicle contains a number of alumi-
num parts. The use of aluminum compo-
nents in motor vehicle engines
necessitates that anticorrosion/antifreeze
coolant used in such engines be specifical-
ly formulated to protect the aluminum
parts. (Failure to use such anticorro-
sion/antifreeze coolant will result in a
significantly shortened service life.)
Therefore, the following product is strongly
recommended for use in your vehicle:
Mercedes-Benz 325.0
anticorrosion/antifreeze agent.
Before the start of the winter season (or
once a year in hot southern regions), you
should have the anticorrosion/antifreeze
concentration checked. The coolant is also
regularly checked each time you bring your
vehicle to an authorized Mercedes-Benz
Center for service.
Page 460 of 481

459 Technical terms
ETD
(E
mergency T
ensioning D
evice)
Device which deploys in certain frontal
and rear collisions exceeding the sys-
tem’s threshold to tighten the seat
belts. ->SRS
FSS PLUS (Canada vehicles)
(F
lexible S
ervice S
ystem PLUS)
Maintenance service indicator in the
multifunction display that informs the
driver when the next vehicle mainte-
nance service is due. FSS PLUS evalu-
ates engine temperature, oil level,
vehicle speed, engine speed, distance
driven and the time elapsed since your
last maintenance service, and calls for
the next maintenance service accord-
ingly.
GAWR
(G
ross A
xle W
eight R
ating)
(
page 344)Gear range*
Number of gears which are available to
the automatic transmission for shifting.
The automatic gear shifting process
can be adapted to specific operating
conditions using the selector lever.
GPS
(G
lobal P
ositioning S
ystem)
Satellite-based system for relaying
geographic location information to and
from vehicles equipped with special re-
ceivers.
GVW
(G
ross V
ehicle W
eight)
(
page 344)
GVWR
(Gross V
ehicle W
eight R
ating)
(
page 345)Head-thorax air bag
Installed in the doors, these air bags
protect occupants during side impact
collisions exceeding a preset thresh-
old. Unlike normal side air bags,
head-thorax air bags are also designed
to provide protection for the head area.
Instrument cluster
The displays and indicator/warning
lamps in the driver’s field of vision, in-
cluding the tachometer, speedometer,
coolant temperature and fuel gauge.
Kickdown*
Depressing the accelerator past the
point of resistance shifts the automatic
transmission down to the lowest possi-
ble gear. This very quickly accelerates
the vehicle and should not be used for
normal acceleration needs.
Kilopascal (kPa)
(
page 345)