Page 324 of 521

323 Operation
Engine compartment
Engine compartment
Hood Opening
Warning!G
Do not pull the release lever while the vehi-
cle is in motion. Otherwise the hood could
be forced open by passing air flow.
This could cause the hood to come loose
and injure you and/or others.
Warning!G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature indicator indicates that the engine
is overheated, do not open the hood. Move
away from vehicle and do not open the hood
until the engine has cooled. If necessary,
call the fire department.
Warning!G
You could be injured when the hood is open
- even when the engine is turned off.
Parts of the engine can become very hot. To
prevent burns, let the engine cool off com-
pletely before touching any components on
the vehicle. Comply with all relevant safety
precautions.
Warning!G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
The radiator fan may continue to run for
approximately 30 seconds or even restart
after the engine has been turned off. Stay
clear of fan blades.
Warning!G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components
(ignition coils, spark plug sockets, diagnos-
tic socket) of the ignition system
with the engine running
while starting the engine
if the ignition is “on” and the engine is
turned manually.
Page 325 of 521

324 Operation
Engine compartment
The hood lock release lever is located to
the left of the steering wheel under the
dashboard.
1Hood lock release lever
Pull lever 1 downwards.
The hood is unlocked.2Lever for opening the hood
Push lever2 under the hood upwards.
Pull up on the hood and then release it.
The hood will be automatically held
open at shoulder height by gas-filled
struts.Closing
Let the hood drop from a height of
approximately 1 ft (30 cm).
The hood will lock audibly.
Check to make sure the hood is fully
closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
!To avoid damage to the windshield wipers or
hood, never open the hood if the wiper arms are
folded forward away from the windshield.
Warning!G
When closing the hood, use extreme caution
not to catch hands or fingers.
Be careful that you do not close the hood on
anyone.
Make sure the hood is securely engaged be-
fore driving off. Do not continue driving if the
hood can no longer engage after an acci-
dent, for example. The hood could otherwise
come loose while the vehicle is in motion
and injure you and/or others.
Page 327 of 521

326 Operation
Engine compartment
CLK 63 AMG
1Oil dipstick
2Upper (max) mark
3Lower (min) markTo check the engine oil level with the oil
dipstick, do the following:
Open the hood (page 323).
Pull out oil dipstick1.
Wipe oil dipstick1 clean.
Fully insert oil dipstick1 into the
dipstick guide tube.
Pull out oil dipstick1 again after
approximately 3 seconds to obtain ac-
curate reading.
The oil level is correct when it is be-
tween the lower (min) mark3 and
upper (max) mark2 of oil dipstick1.
If necessary, add engine oil.
For adding engine oil, see “Adding en-
gine oil” (
page 327).
For more information on engine oil, see
“Fuels, coolants, lubricants, etc.”
(
page 489).
For more information on messages in the
multifunction display concerning engine
oil, see the “Practical hints” section
(
page 409).
iCLK 350:
The filling quantity between the upper and lower
marks on the oil dipstick is approximately
2.1 US qt. (2.0 l).
CLK 550 / CLK 63 AMG:
The filling quantity between the upper and lower
marks on the oil dipstick is approximately
1.6 US qt. (1.5 l).
Page 329 of 521

328 Operation
Engine compartment
Coolant
The engine coolant is a mixture of water
and anticorrosion/antifreeze.
When checking the coolant level,
the vehicle must be parked on level
ground
the coolant temperature must be be-
low 158°F (70°C)
The coolant expansion tank is located on
the passenger side of the engine
compartment.
1Coolant expansion tank
2Cap
Using a rag, turn cap 2 slowly
approximately one half turn counter-
clockwise to release any excess
pressure.
Continue turning the cap 2 counter-
clockwise and remove it.
The coolant level is correct if the level
for cold coolant: reaches the marking
(plastic bridge) inside the reservoir
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap 2.
More information on coolant can be found
in the “Technical data” section
(
page 494).
Warning!G
In order to avoid potentially serious burns:
Use 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 indicator
indicates that the coolant is overheated.
Do not remove pressure cap on coolant
reservoir if the coolant temperature is
above 158°F (70°C). Allow the coolant
to cool down before removing cap.
The coolant reservoir contains hot fluid
and is under pressure.
Using a rag, slowly open the cap approx-
imately 1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.
Page 374 of 521

373 Operation
Vehicle care
Cleaning the windows and the wiper
blades
Make sure the hood is fully closed.
Make sure the vehicle’s on-board
electronics have status0 (
page 38).
Fold the wiper arms forward until they
snap into place.
Clean the wiper blade inserts with a
clean cloth and detergent solution.
Use a soft, clean cloth and a mild
window cleaning solution on all outside
and inside glass surfaces.
An automotive glass cleaner is
recommended.
!Do not apply strong pressure to the sensor
covers. Applying strong pressure may damage
the sensor covers.
Follow the instructions provided by the power
washer manufacturer on maintaining a distance
between the vehicle and the nozzle of the power
washer.
!To prevent scratches, never apply strong
force and only use a soft, non-scratching cloth
when cleaning the sensors. Do not attempt to
wipe dirty sensors with a dry cloth or sponge.
!Never open the hood when the wiper arms
are folded forward.
Warning!G
For safety reasons, switch off wipers and
remove SmartKey from starter switch
(vehicles with KEYLESS-GO*: Make sure the
vehicle's on-board electronics have
status0) before cleaning the windshield
and/or the wiper blades. Otherwise, the
wiper motor could suddenly turn on and
cause injury.
!Do not pull on the wiper blade inserts. They
could tear.
!Fold the windshield wiper arms back onto
the windshield before turning the SmartKey in
the starter switch or pressing the KEYLESS-GO
start/stop button (vehicles with KEYLESS-GO*).
Hold on to the wiper when folding the wiper arm
back. If released, the force of the impact from
the tensioning spring could crack the windshield.
!To clean the window interior, do not use a
dry cloth, abrasives, solvents or cleaners
containing solvents. Do not touch the inside of
the front, rear or side windows with hard objects
such as an ice scraper or ring. Doing so may
damage the windows.
Page 384 of 521

383 Practical hints
What to do if …?
During severe operating conditions, e.g.
stop-and-go traffic, the coolant tempera-
ture may rise close to 248°F (120°C).
ProblemPossible cause/consequenceSuggested solution
•The red coolant warning lamp
comes on while driving and you
hear a warning sound.The coolant temperature has exceeded
248 °F (120 °C).Stop in a safe location as soon as pos-
sible and allow the engine and coolant
to cool down.
Warning!G
Driving when your engine is overheated 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 which can occur just by open-
ing 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.
Page 408 of 521

407 Practical hints
What to do if …?
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
•Observe the coolant temperature indicator in
the instrument cluster (
page 28).
If the temperature rises again:
Contact an authorized Mercedes-Benz
Center immediately.
•The cooling fan for the coolant is mal-
functioning.Observe the coolant temperature indicator in the
instrument cluster (
page 28).
Have the fan replaced as soon as possible.
Warning!G
Driving when your engine is overheated 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 which can occur just by open-
ing 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). Do-
ing so may cause serious engine damage which
is not covered by the Mercedes-Benz Limited
Warranty.
Page 447 of 521

446 Practical hints
Replacing bulbs
Replacing bulbs for front lamps
Before you start to replace a bulb for a
front lamp, do the following first:
Turn the exterior lamp switch to
positionM (
page 129).
Open the hood (page 323).
Front lamps halogen-type
1Housing cover for low beam headlamp
2Housing cover for high beam head-
lamp, parking and standing lamp3Bulb socket for turn signal lamp bulb
4Bulb holder of low beam bulb
5Bulb holder of high beam bulb
6Bulb socket for parking and standing
lamp bulb
Low beam bulb
Turn housing cover1 counterclock-
wise and remove it.
Turn bulb holder4 with the bulb coun-
terclockwise and remove it.
Pull the bulb at its socket out of bulb
holder4.
Insert the new bulb so that its socket
locates in the recess of bulb holder4
and is level to it.
Reinsert bulb holder4 with the bulb in
the lamp and turn clockwise.
Align housing cover1 and turn it
clockwise.
High beam bulb
Turn housing cover2 counterclock-
wise and remove it.
Turn bulb holder5 with the bulb coun-
terclockwise and remove it.
Pull the bulb at its socket out of bulb
holder5.
Insert the new bulb so that its socket
locates in the recess of bulb holder5
and is level to it.
Reinsert bulb holder5 with the bulb in
the lamp and turn clockwise.
Align housing cover2 and turn it
clockwise.