Page 305 of 489

304 OperationDriving instructions
Coolant temperature
During severe operating conditions and
stop-and-go city traffic, the coolant
temperature may rise close to
approximately 248°F (120°C).
The engine should not be operated with
the coolant temperature over 248°F
(120°C). Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Warning!
G
Inhalation of exhaust gas is hazardous to
your health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause un-
consciousness and lead to death.
Do not run the engine in confined areas
(such as a garage) which are not properly
ventilated. If you think that exhaust gas
fumes are entering the vehicle while driving,
have the cause determined and corrected
immediately. If you must drive under these
conditions, drive with at least one window
fully open at all times.
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 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.
Page 306 of 489

305 Operation
At the gas station
At the gas station
Refueling
The fuel filler flap is located on the
right-hand side of the vehicle towards the
rear. Locking/unlocking the vehicle with
the SmartKey or the SmartKey with
KEYLESS-GO* automatically locks/un-
locks the fuel filler flap.1To open the fuel filler flap
2To insert the fuel filler cap
Turn the engine off
by turning the SmartKey to
position0. Remove the SmartKey
from the starter switch.
by pressing the KEYLESS-GO*
start/stop button. Open the driv-
er’s door (with driver’s door open,
starter switch is now in position0,
same as with SmartKey removed
from starter switch).
Open the fuel filler flap by pushing at
the point indicated by the arrow 1.
The fuel filler flap springs open.
Turn fuel cap counterclockwise and
hold on to it until possible pressure is
released.
Warning!
G
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious inju-
ry. Whenever you are around gasoline, avoid
inhaling fumes and skin contact, extinguish
all smoking materials. Never allow sparks,
flame or smoking materials near gasoline!
Failure to remove the fuel cap slowly could
result in personal injury.
iIn cases where the central locking sys-
tem is not releasing the fuel filler flap,
or the opening mechanism is clamping,
notify Roadside Assistance or an au-
thorized Mercedes-Benz Center.
Page 307 of 489

306 OperationAt the gas station
Take off cap and set it in the direction
of arrow 2 in the recess on the fuel fill-
er flap.
To prevent fuel vapors from escaping
into open air, fully insert filler nozzle
unit.
Only fill your tank until the filler nozzle
unit cuts out – do not top up or
overfill.
Replace fuel cap by turning it clockwise
until it audibly engages.
Close fuel filler flap.Warning!
G
Overfilling of the fuel tank may create
pressure in the system which could cause a
gas discharge. This could cause the gas to
spray back out when removing the fuel
pump nozzle, which could cause personal
injury.
iOnly use premium unleaded gasoline
with a minimum Posted Octane Rating
of 91 (average of 96 RON / 86 MON).
Information on gasoline quality can
normally be found on the fuel pump.
For more information on gasoline, see
“Premium unleaded gasoline”
(page 455) or the Factory Approved
Service Products pamphlet.
iLeaving the engine running and the fuel
cap open can cause theú malfunc-
tion indicator lamp (USA only) or
the± malfunction indicator lamp
(Canada only) to illuminate.
More information can be found in the
“Practical hints” section (
page 362).
Page 308 of 489

307 Operation
At the gas station
Check regularly and before a long tripEngine compartment (CLK 500, example)1Coolant level
2Brake fluid (fuse box cover removed)
3Windshield washer and headlamp
cleaning system*Coolant
For normal replenishing, use water (pota-
ble water quality). For more information,
see “Coolant” (
page 314) and see “Fu-
els, coolants, lubricants, etc.”
(
page 452).
Brake fluid
Removing fuse box cover,
see (page 437).Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield washer
system and headlamp cleaning system*”
(
page 316).
Engine oil level
For more information on engine oil, see
“Engine oil” (
page 309).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
“Replacing bulbs” (
page 412).
For more information, see “Exterior lamp
switch” (
page 52).
Tire inflation pressure
For more information, see “Checking tire
inflation pressure” (
page 328).
iOpening the hood, see (
page 308).
!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks immediately.
Notify an authorized Mercedes-Benz
Center immediately. Do not add brake
fluid as this will not solve the problem.
For more information, see also “Practi-
cal hints” (
page 361).
Page 309 of 489

308 OperationEngine compartmentHood
Opening
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.
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.
!To avoid damage to the windshield wip-
ers or hood, never open the hood if the
wiper arms are folded forward away
from the windshield.
Warning!
G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running. Make sure the hood is
properly closed before driving. When closing
the hood, use extreme caution not to catch
hands or fingers.
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.
Page 310 of 489

309 Operation
Engine compartment
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.
Engine oil
The amount of oil your engine needs will
depend on a number of factors, including
driving style. Higher oil consumption can
occur when
the vehicle is new
the vehicle is driven frequently at
higher engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
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
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.
Warning!
G
Be careful that you do not close the hood on
anyone.
iDo not use any special lubricant addi-
tives, as these may damage the drive
assemblies. Using special additives not
approved by Mercedes-Benz may
cause damage not covered by the
Mercedes-Benz Limited Warranty.
More information on this subject is
available at any Mercedes-Benz
Center.
Page 311 of 489

310 OperationEngine compartmentChecking engine oil level with the con-
trol system, CLK 500
When checking the oil level
the vehicle must be parked on level
ground
with the engine at operating tempera-
ture, the vehicle must have been
stationary for at least 5 minutes with
the engine turned off
with the engine not at operating tem-
perature yet, the vehicle must have
been stationary for at least 30 minutes
with the engine turned off
To check the engine oil level via the
multifunction display, do the following:
Switch on the ignition (
page 36).
The standard display (
page 148) should
appear in the multifunction display.
Press buttonk or j on the mul-
tifunction steering wheel until the fol-
lowing message is seen in the
multifunction display:One of the following messages will
subsequently appear in the multifunc-
tion display:
Engine oil level
ok
Add 1.0 qt.
to reach max. oil level(Canada:
1.0 liter
)
Add 1.5 qt.
to reach max. oil level(Canada:
1.5 liter
)
Add 2.0 qt.
to reach max. oil level(Canada:
2.0 liter
)
If necessary, add engine oil.
For adding engine oil, see (
page 312).
For more information on engine oil, see the
“Technical data” section (
page 452) and
(
page 454).
Other display messages
If the SmartKey is not turned to position2
in the starter switch, the following
message will appear:
Turn on ignition
to see engine oil level
Switch on the ignition (
page 36).
iIf you want to interrupt the checking
procedure, press thek orj
button on the multifunction steering
wheel.
Page 312 of 489

311 Operation
Engine compartment
If you see the message:Observe waiting time
If engine is at operating temperature,
wait 5 minutes before repeating check
procedure.
If engine is not at operating
temperature yet, wait 30 minutes
before repeating check procedure.
If you see the message:
Engine oil level
Not when engine on
Turn off the engine.
If the engine is at operating
temperature, wait 5 minutes before
checking oil.
If the engine is not at operating
temperature yet, you must wait
30 minutes before checking oil.If there is excess engine oil with the engine
at operating temperature, the following
message will appear:
Engine oil level
Reduce oil level
Have excess oil siphoned or drained
off. Contact an authorized
Mercedes-Benz Center.
For more information on messages in the
multifunction display concerning engine
oil, see the “Practical hints” section
(
page 388).Checking engine oil level with the oil
dipstick, CLK 350
When checking the oil level
the vehicle must be parked on level
ground.
with the engine at operating tempera-
ture yet, the vehicle must have been
stationary for at least 5 minutes with
the engine turned off.
with the engine not at operating tem-
perature, the vehicle must have been
stationary for at least 30 minutes with
the engine turned off.
!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.