2008 MERCEDES-BENZ CLK350 engine

312 Operation
Driving instructions
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine gradually. Do not
place full load on the engine until the oper-
ating temperature has been reached.Parking
Warning!G
New vehicle brake pads and discs, and
replacement brake pads and discs may take
several hundred miles of driving until they
provide optimum braking efficiency. Until
that time, you may need to use increased
brake pedal pressure while braking. Please
be aware of this and adjust your driving and
braking accordingly during this break-in
period.
Excessive high demand braking will cause
correspondingly high brake wear. Please be
attentive to the brake warning lamp in the
instrument cluster and brake condition mes-
sages in the multifunction display.
Especially for high performance driving, it is
important to maintain and have the brake
system checked regularly.
!When driving off on a slippery surface, do
not allow a drive wheel to spin for an extended
period with the ESP
® switched off. Doing so may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.
!Simultaneously depressing the accelerator
pedal and applying the brakes reduces engine
performance and causes premature brake wear
and drivetrain wear.
Warning!G
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury, or
damage to the vehicle or the vehicle
drivetrain, as a result of vehicle movement,
always do the following before turning off
the engine and leaving the vehicle:

Keep right foot firmly on brake pedal.

Firmly depress parking brake pedal.

Move the gear selector lever to
positionP.

Slowly release brake pedal.

When parked on an incline, always turn
the front wheels towards the road curb.

316 Operation
Driving instructions
Winter driving instructions
The most important rule for slippery or icy
roads is to drive sensibly and to avoid
abrupt acceleration, braking and steering
maneuvers. Do not use the cruise control
system under such conditions.
When the vehicle is in danger of skidding,
move gear selector lever to position N. Try
to keep the vehicle under control by cor-
rective steering action.Road salts and chemicals can adversely af-
fect braking efficiency. Increased pedal
force may become necessary to produce
the normal braking effect.
Depressing the brake pedal periodically
when traveling at length on salt-strewn
roads can bring road-salt-impaired braking
efficiency back to normal.
If the vehicle is parked after being driven
on salt-treated roads, the braking efficien-
cy should be tested as soon as possible af-
ter driving is resumed.
For more information, see “Winter driving”
(
page 362).
iFor information on driving with snow chains,
see “Snow chains” (
page 363).
Warning!G
On slippery road surfaces, never downshift
in order to obtain braking action. This could
result in drive wheel slip and reduced vehi-
cle control. Your vehicle’s ABS will not pre-
vent this type of control loss.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.
Warning!G
If the vehicle becomes stuck in snow, make
sure snow is kept clear of the exhaust pipe
and from around the vehicle with the engine
running. Otherwise, deadly carbon monox-
ide (CO) gases may enter vehicle interior re-
sulting in unconsciousness and death.
To assure sufficient fresh air ventilation,
open a window slightly on the side of the ve-
hicle not facing the wind.
Warning!G
The outside temperature indicator is not de-
s i g n e d t o s e r v e a s a n i c e - w a r n i n g d e v i c e a n d
is therefore unsuitable for that purpose. In-
dicated temperatures just above the freez-
ing point do not guarantee that the road
surface is free of ice.

317 Operation
Driving instructions
Standing waterPassenger compartment
Driving abroad
Abroad, there is an extensive
Mercedes-Benz service network at your
disposal. If you plan to drive into areas
which are not listed in the index of your
Mercedes-Benz Center directory, you
should request pertinent information from
an authorized Mercedes-Benz Center.Control and operation of radio trans-
mitters
COMAND*, radio and telephone*
!Do not drive through flooded areas or water
of unknown depth. Before driving through water,
determine its depth. Never accelerate before
driving into water. The bow wave could force wa-
ter into the engine and auxiliary equipment, thus
damaging them.
If you must drive through standing water, drive
slowly to prevent water from entering the pas-
senger compartment or the engine compart-
ment. Water in these areas could cause damage
to electrical components or wiring of the engine
or transmission, or could result in water being in-
gested by the engine through the air intake,
causing severe internal engine damage. Any
such damage is not covered by the
Mercedes-Benz Limited Warranty.
Warning!G
Always fasten items being carried as
securely as possible.
In an accident, during hard braking or sud-
den maneuvers, loose items will be thrown
around inside the vehicle, and cause injury
to vehicle occupants unless the items are
securely fastened in the vehicle.
The trunk is the preferred place to carry
objects.
Warning!G
Please do not forget that your primary re-
sponsibility is to drive the vehicle safely.
Only operate the COMAND (Cockpit Man-
agement and Data System), radio or tele-
phone
1 if road, weather and traffic
conditions permit.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h), your vehicle is
covering a distance of 44 feet
(approximately 14 m) every second.
1Observe all legal requirements.

318 Operation
Driving instructions
Telephones* and two-way radios
Radio transmitters, such as a mobile
phone or a citizens band unit should only
be used inside the vehicle if they are con-
nected to an antenna that is installed on
the outside of the vehicle.
Refer to the radio transmitter operation in-
structions regarding use of an external
antenna.Catalytic converter
Your Mercedes-Benz is equipped with
monolithic-type catalytic converters, an
important element in conjunction with the
oxygen sensors to achieve substantial con-
trol of the pollutants in the exhaust emis-
sions. Keep your vehicle in proper
operating condition by following our
recommended maintenance instructions
as outlined in your Maintenance Booklet.
Emission control
Certain systems of the engine serve to
keep the toxic components of the exhaust
gases within permissible limits required by
law.
These systems, of course, will function
properly only when maintained strictly ac-
cording to factory specifications. Any ad-
justments to the engine should therefore
be carried out only by qualified
Mercedes-Benz Center authorized techni-
cians.
Warning!G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system, pos-
sibly resulting in an accident and/or serious
personal injury.
!To prevent damage to the catalytic
converters, only use premium unleaded gasoline
in this vehicle.
Any noticeable irregularities in engine operation
should be repaired promptly. Otherwise, exces-
sive unburned fuel may reach the catalytic con-
verter, causing it to overheat and potentially
start a fire.
Warning!G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay, or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.

319 Operation
Driving instructions
Engine adjustments should not be altered
in any way. Moreover, the specified service
jobs must be carried out regularly accord-
ing to Mercedes-Benz servicing require-
ments. For details refer to the
Maintenance Booklet.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.

320 Operation
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 capTurn off the engine
Vehicles with SmartKey: Remove the
SmartKey from the starter switch.
Vehicles with KEYLESS-GO*: Open the
driver’s door (with driver’s door open,
starter switch is now in position0,
same as with SmartKey removed from
starter switch). The driver’s door then
can be closed again.
Open the fuel filler flap by pushing at
the point indicated by arrow 1.
The fuel filler flap springs open.
Turn the 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 per-
sonal injury.
Never allow sparks, flame or smoking mate-
rials near gasoline!
Turn off the engine before refueling.
Whenever you are around gasoline, avoid in-
haling fumes and skin or clothing contact,
extinguish all smoking materials.
Direct skin contact with fuels and the inha-
lation of fuel vapors can damage to your
health.
iIn cases where the central locking system is
not releasing the fuel filler flap, or the opening
mechanism is clamping, notify Roadside Assis-
tance or an authorized Mercedes-Benz Center.

321 Operation
At the gas station
Take off the fuel cap and set it in the di-
rection of arrow 2 in the recess on the
fuel filler flap.
To prevent fuel vapors from escaping
into open air, fully insert the filler noz-
zle unit.
Only fill your tank until the filler nozzle
unit cuts out – do not top off or
overfill.
Replace the fuel cap by turning it
clockwise until it audibly engages.
Close the 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.
iMake sure to close the fuel filler flap before
locking your vehicle as the flap locking pin
prevents closing after you have locked the
vehicle.
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. Please contact gas sta-
tion personnel in case labels on the pump cannot
be found.
For more information on gasoline, see “Premium
unleaded gasoline” (
page 492), or the Factory
Approved Service Products pamphlet (USA only),
or contact an authorized Mercedes-Benz Center.
iLeaving the engine running and the fuel cap
open can cause theú malfunction indicator
lamp (USA only) or the± malfunction indica-
tor lamp (Canada only) to illuminate.
More information can be found in the “Practical
hints” section (
page 381).

322 Operation
At the gas station
Check regularly and before a long trip
Engine compartment (CLK 550, 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 328) and see “Fu-
els, coolants, lubricants, etc.”
(
page 489).
Brake fluid
Removing fuse box cover,
see (
page 473).Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield washer
system and headlamp cleaning system*”
(
page 330).
Engine oil level
For more information on engine oil, see
“Engine oil” (
page 325).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
“Replacing bulbs” (
page 443).
For more information, see “Exterior lamp
switch” (
page 55).
Tire inflation pressure
For more information, see “Checking tire
inflation pressure” (
page 341).
iOpening the hood, see (page 323).
!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 380).