2017 MERCEDES-BENZ CLS engine overheat

boosting effect. You will require considerably
more effort to steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
G WARNING
If the parking brake has not been fully
released when driving, the parking brake can: R
overheat and cause a fire R
lose its hold function.
There is a risk of fire and an accident. Release
the parking brake fully before driving off.
! Do not warm up the engine with the vehicle
stationary. Drive off immediately. Avoid high
engine speeds and driving at full throttle until
the engine has reached its operating temper-
ature.
Only shift the automatic transmission to the
desired drive position when the vehicle is sta-
tionary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery roads.
You could otherwise damage the drive train.
! Mercedes-AMG vehicles: at low engine oil
temperatures below 68 ‡ (+20 †), the max-
imum engine speed is restricted in order to
protect the engine. To protect the engine and
maintain smooth engine operation, avoid driv-
ing at full throttle when the engine is cold.
SmartKey positions
SmartKey
Z
To remove the SmartKey
(shift the transmission to position P ) G
Power supply for some consumers, such as
the windshield wipers H
Ignition (power supply for all consumers)
and drive position I
To start the engine
i The SmartKey can be turned in the ignition
lock even if it is not the correct SmartKey for
the vehicle. The ignition is not switched on.
The engine cannot be started.
KEYLESS-GO General notes Vehicles with KEYLESS-GO are equipped with
SmartKeys featuring the integrated KEYLESS-
GO function and a detachable Start/Stop but-
ton.
The Start/Stop button must be inserted in the
ignition lock and the SmartKey must be in the
vehicle.
When you insert the Start/Stop button into the
ignition lock, the system needs approximately
two seconds recognition time. You can then use
the Start/Stop button.
Pressing the Start/Stop button several times in
succession corresponds to the different Smart-
Key positions in the ignition lock. This is only the
case if you are not depressing the brake pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts immedi-
ately.
A check which periodically establishes a radio
connection between the vehicle and the Smart-
Key determines whether a valid SmartKey is in
the vehicle. This occurs, for example, when
starting the engine.
To start the vehicle without actively using the
SmartKey: R
the Start/Stop button must be inserted in the
ignition lock. R
the SmartKey must be in the vehicle. R
the vehicle must not be locked with the
SmartKey or KEYLESS-GO ( Y
page 76).
Do not keep the KEYLESS-GO key: R
with electronic devices, e.g. a mobile phone
or another SmartKey. R
with metallic objects, e.g. coins or metal foil. R
inside metallic objects, e.g. a metal case.
This can affect the functionality of KEYLESS-GO. Driving 123
Driving and parking Z

change dynamically at the beginning of the
journey. On longer journeys, there are fewer
changes. For more dynamic changes, carry
out a manual reset.
For further information on the ECO display, see
( Y
page 191).
Braking
Important safety notes
G WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients
! On long and steep gradients, you must
reduce the load on the brakes by shifting to a
lower gear in good time. This allows you to
take advantage of the engine's braking effect.
This helps you to avoid overheating the
brakes and wearing them out excessively.
When you take advantage of engine braking, a
drive wheel may not turn for some time, e.g.
on a slippery road surface. This could cause
damage to the drive train. This type of damage
is not covered by the Mercedes-Benz war-
ranty.
Change into a lower gear in good time on long
and steep downhill gradients. This is especially
important if the vehicle is laden.
Heavy and light loads
G WARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This
increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time. ! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short while. This allows the airflow
to cool the brakes more quickly.
Wet roads If you have driven for a long time in heavy rain
without braking, there may be a delayed reac-
tion from the brakes when braking for the first
time. This may also occur after the vehicle has
been washed or driven through deep water.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehicle
washed, brake firmly while paying attention to
the traffic conditions. This will warm up the
brake discs, thereby drying them more quickly
and protecting them against corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance. R
In order to prevent any salt build-up, apply the
brakes occasionally while paying attention to
the traffic conditions. R
Carefully depress the brake pedal and the
beginning and end of a journey. R
Maintain a greater distance to the vehicle
ahead.
Servicing the brakes
! The brake fluid level may be too low, if: R
if the red brake warning lamp lights up in
the instrument cluster and R
you hear a warning tone while the engine is
running
Observe additional warning messages in the
multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines. Driving tips 145
Driving and parking Z

thought out system – for the safety of the vehi-
cle occupants and that of other road users.
Further information on driving safety systems
( Y
page 64).
Cruise control
General notes Cruise control maintains a constant road speed
for you. It brakes automatically in order to avoid
exceeding the set speed. On long and steep
downhill gradients, especially if the vehicle is
laden, you must shift to a lower gear in time. By
doing so, you will make use of the braking effect
of the engine. This relieves the load on the brake
system and prevents the brakes from overheat-
ing and wearing too quickly.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a steady
speed for a prolonged period. You can store any
road speed above 20 mph (30 km/h).
Important safety notes If you fail to adapt your driving style, cruise con-
trol can neither reduce the risk of an accident
nor override the laws of physics. Cruise control
cannot take into account the road, traffic and
weather conditions. Cruise control is only an
aid. You are responsible for maintaining a safe
distance to the vehicle in front, for vehicle
speed, for braking in good time and for staying in
lane.
Do not use cruise control: R
in road and traffic conditions which do not
allow you to maintain a constant speed, e.g. in
heavy traffic or on winding roads R
on slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid R
when there is poor visibility, e.g. due to fog,
heavy rain or snow
If there is a change of drivers, advise the new
driver of the speed stored.
i The speed indicated in the speedometer
may differ slightly from the speed stored. Cruise control lever
C
Activates or increases speed D
Activates or reduces speed

Important safety notes
G WARNIN G
If you operate information systems and com-
munication equipmen t integrate d in th e vehi-
cle while driving , you will be distracte d from
traffic conditions. You could also lose control
of th e vehicle. Ther e is a ris k of an accident.
Only operate th e equipmen t when th e traffic
situation permits. If you are no t sur e that this
is possible , park th e vehicl e payin g attention
to traffic condition s and operate th e equip-
men t when th e vehicl e is stationary.
You must observ e th e legal requirements for th e
country in whic h you are currentl y driving when
operating th e on-board computer.
G WARNIN G
If th e instrumen t cluste r has faile d or mal-
functioned, you may no t recognize function
restriction s in systems relevan t to safety. The
operating safet y of your vehicl e may be
impaired . Ther e is a ris k of an accident.
Drive on carefully. Hav e th e vehicl e checke d
at a qualified specialist workshop immedi-
ately.
The on-board computer only shows message s or
warning s from certain systems in th e multifunc-
tion display. You should therefor e mak e sur e
your vehicl e is operating safely at all times .
If th e operating safet y of your vehicl e is
impaired , pull ove r as soo n as it is saf e to do so.
Contac t a qualified specialist workshop.
Fo r an overview, see th e instrumen t panel illus-
tration ( Y
page 34).
Displays and operation
Speedometer with segments
The segments in th e speedometer indicat e
whic h spee d range is available.R
Cruis e control activated ( Y
page 148):
The segments ligh t up from th e store d spee d
to th e en d of th e scale.R
DISTRONI C PLU S activated ( Y
page 149): On e or two segments in th e set spee d range
ligh t up. R
DISTRONI C PLU S detects a vehicl e in fron t
moving mor e slowly than th e store d speed:
The segments between th e spee d of th e vehi-
cle in fron t and th e store d spee d ligh t up.
Tachometer
! Do no t driv e in th e overrevving range, as this
could damag e th e engine.
The red ban d in th e tachometer indicates th e
engine's overrevving range.
The fuel suppl y is interrupted to protect th e
engin e when th e red ban d is reached.
Outside temperature display You should pay special attention to road condi-
tion s when temperatures are aroun d freezing
point.
Bea r in min d that th e outside temperature dis-
play indicates th e temperature measured and
does no t record th e road temperature.
The outside temperature display is in th e multi-
function display ( Y
page 190).
The multifunction display shows changes in th e
outside temperature wit h a delay.
Coolant temperature gauge
G WARNIN G
Opening th e hoo d when th e engin e is over-
heated or when there is a fir e in th e engin e
compartmen t could expos e you to hot gase s
or other servic e products . Ther e is a ris k of
injury.
Let an overheate d engin e cool down before
opening th e hood. If there is a fir e in th e
engin e compartment, keep th e hoo d closed
and contact th e fir e department.
! A display message is shown if th e coolan t
temperature is to o high .
If th e coolan t temperature is ove r 24 8 ‡
(12 0 †), do no t continue driving . The engin e
will otherwise be damaged.188
Displays and operation
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
= See Operator' s Man ‐
ual The battery is no t bein g charged.
A warning tone also sounds.
Possibl e causes are: R
a defective alternato rR
a torn poly-V-belt R
a malfunction in th e electronics
! Do no t continu e driving. The engin e could otherwise overheat.X
Pull ove r and stop th e vehicl e safely and switch off th e engine, pay-
ing attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Consult a qualified specialist workshop .
= Sto p Vehicl e See
Operator' s Manual The battery is no longer bein g charged and th e battery charg e level is
to o low.
A warning tone also sounds. X
Pull ove r and stop th e vehicl e safely and switch off th e engine, pay-
ing attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Observ e th e instruction s in th e = See Operator' s Manual
display message .X
Consult a qualified specialist workshop .

Engine compartment
Hood
Important safety notes
G WARNING
If the hood is unlatched, it may open up when
the vehicle is in motion and block your view.
There is a risk of an accident.
Never unlatch the hood while driving. Before
every trip, ensure that the hood is locked.
G WARNING
When opening and closing the hood, it may
suddenly fall into the closed position. There is
a risk of injury to persons within range of
movement of the hood.
Open and close the hood only when no one is
within its range of movement.
G WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
G WARNING
The engine compartment contains moving
components. Certain components, such as
the radiator fan, may continue to run or start
again suddenly when the ignition is off. There
is a risk of injury.
If you need to do any work inside the engine
compartment: R
switch off the ignition R
never reach into the area where there is a
risk of danger from moving components,
such as the fan rotation area R
remove jewelry and watches R
keep items of clothing and hair, for exam-
ple, away from moving parts
G WARNING
The ignition system and the fuel injection sys-
tem work under high voltage. If you touch
components which are under voltage, you
could get an electric shock. There is a risk of
injury.
Never touch components of the ignition sys-
tem or fuel injection system when the ignition
is switched on.
Opening the hood
G WARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following.
G WARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured by
the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
! Make sure that the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield wip-
ers or the hood.Engine compartment 265
Maintenance and care Z

Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
General notes Depending on your driving style, the vehicle
consumes up to 0.8 US qt (0.8 liters) of oil per
600 miles (1,000 km). The oil consumption may
be higher than this when the vehicle is new or if
you frequently drive at high engine speeds.
Depending on the engine, the oil dipstick may be
in a different location.
When checking the oil level: R
park the vehicle on a level surface R
the engine should be switched off for approx-
imately five minutes if the engine is at normal
operating temperature R
if the engine is not at normal operating tem-
perature, e.g. if the engine was only started
briefly, wait about 30 minutes before carrying
out the measurement
Checking the oil level using the oil dip-
stick
Example X
Pull oil dipstick C out of the dipstick guide
tube. X
Wipe off oil dipstick C .X
Slowly slide oil dipstick C into the guide tube
to the stop, and take it out again.
If the level is between MIN mark

Additional service products
Import ant safety notes
G WARNIN G
Certain component s in th e engin e compart-
ment, suc h as th e engine, radiato r and part s
of th e exhaust system, can become ver y hot .
Working in th e engin e compartmen t poses a
ris k of injury.
Wher e possible, let th e engin e cool down and
touch only th e component s described in th e
following.
G WARNIN G
The engin e compartmen t contain s moving
components. Certain components, suc h as
th e radiato r fan , may continu e to run or start
again suddenly when th e ignition is off . There
is a ris k of injury.
If you need to do any wor k inside th e engin e
compartment: R
switch off th e ignitionR
never reac h int o th e area wher e there is a
ris k of danger from moving components,
suc h as th e fan rotation areaR
remove jewelr y and watchesR
keep items of clothing and hair , for exam-
ple, away from moving part s
G WARNIN G
The coolin g system is pressurized, particularly
when th e motor is warm . If you open th e cap ,
you could be scalded if hot coolan t sprays out .
There is a ris k of injury.
Let th e engin e cool down before you open th e
cap . Wear gloves and eye protection . Slowly
open th e cap to reliev e pressure.
G WARNIN G
Opening th e hoo d when th e engin e is over-
heated or when there is a fir e in th e engin e
compartmen t could expos e you to hot gase s
or other servic e products . There is a ris k of
injury. Let an overheate d engin e cool down before
opening th e hood. If there is a fir e in th e
engin e compartment, keep th e hoo d closed
and contact th e fir e department.
Checking coolant level
Exampl e X
Park th e vehicl e on a level surface.
Only chec k th e coolan t level when th e vehicl e
is on a level surfac e and th e engin e has cooled
down . X
Turn th e SmartKey to position 2 in th e ignition
loc k ( Y
page 123).
or X
On vehicles wit h KEYLESS-GO , press th e
Start/Sto p butto n twice ( Y
page 123).X
Chec k th e coolan t temperature display in th e
instrumen t cluster.
The coolan t temperature mus t be belo w
15 8 ‡ (70 †). X
Turn th e SmartKey to position 0 in th e ignition
loc k ( Y
page 123).
or X
Press th e Start/Sto p butto n once on vehicles
wit h KEYLESS-GO ( Y
page 123).X
Slowly tur n cap C half a tur n counter-clock -
wise and allow excess pressur e to escape.X
Turn cap C further counter-clockwise and
remove it .
If th e coolan t is at th e level of marke r bar