engine overheat MERCEDES-BENZ GLC SUV 2015 Owners Manual

for example, the power steering and the brake
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 when the vehi-
cle is stationary. Drive off immediately.
Avoid high engine speeds and driving at full throttle until the engine has reached its
operating temperature.
Only shift the automatic transmission to
the desired drive position when the vehicle is stationary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. You could otherwise damage the
drive train.
Observe the important safety notes for PLUG-
IN HYBRID vehicles (Y page 44). Key positions
Key g
To remove the key
1 Power supply for some consumers, such
as the windscreen wipers
2 Ignition (power supply for all consumers)
and drive position
3 To start the vehicle
i If the key does not belong to the vehicle, it
can still be turned in the ignition lock. How-
ever, the ignition will not be switched on.
The engine cannot be started.
Start/Stop button General notes
When you insert the Start/Stop button into
the ignition lock, the system needs approx-
imately 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
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 key
determines whether a valid key is in the vehi-
cle. This occurs, for example, when starting
the engine. Driving
187Driving and parking Z

time, the driver has adopted the most eco-
nomical driving style for the selected settings
and prevailing conditions. The ECO display
border lights up.
The ECO display does not indicate the actual fuel consumption. The additionally achieved
range displayed under Bonus fr. start
Bonus fr. start
does not indicate a fixed consumption reduc-
tion.
In addition to driving style, the actual con-
sumption is affected by other factors, such
as:
R load
R tyre pressure
R cold start
R choice of route
R the use of electrical consumers
These factors are not included in the ECO dis-
play.
An economical driving style involves driving at a moderate engine speed.
To achieve a higher value in the categories
"acceleration" and "smooth driving":
R observe the gearshift recommendation
R drive the vehicle in drive program E
On long journeys at a constant speed, e.g. on the motorway, only the outer area for "con-
stant" will change.
The ECO display summarises the driving style
from the start of the journey to its completion. Therefore, there are more marked changes in
the outer areas at the start of a journey. Dur- ing a prolonged driving time, these changes
are smaller. For more marked changes, per-
form a manual reset (Y page 319).
Further information on the ECO display
(Y page 318). Brakes
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.
This increases the risk of skidding and having
an accident.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients Change into a lower gear in good time on long
and steep downhill gradients. Take particular note of this when driving a laden vehicle and
when towing a trailer.
This also applies if cruise control, DISTRONIC
PLUS or SPEEDTRONIC are activated.
This will use the braking effect of the engine,
so less braking will be required to maintain
vehicle speed. This relieves the load on the
brake system and prevents the brakes from
overheating and wearing too quickly.
Heavy and light loads G
WARNING
The braking system can overheat if you leave your foot on the brake pedal while driving.
This increases the braking distance and could
even cause the braking system to fail. There is
a risk of an accident.
Never use the brake pedal as a footrest. Do
not simultaneously depress both the brake
pedal and the accelerator pedal while driving.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If heavy demands are made on the brakes, do not park the vehicle immediately. Drive on for
a short while. This allows the airflow to cool
the brakes more quickly. 224
Driving
tipsDriving an d parking

Hill start assist will aid you when pulling away
on a hill. For further information about hill
start assist, see (Y page 191).
Do not shift into transmission position N
when driving off-road. You could lose control
of the vehicle if you attempt to brake the
vehicle using the service brake. If the gradient
is too steep for your vehicle, back up in
reverse gear.
Always observe the approach/departure
angle values (Y page 489).
Maximum gradient-climbing capability Always observe the maximum gradient climb-
ing ability values (Y page 489).
Hilltops When driving up an uphill gradient, slightly
reduce pressure on the accelerator immedi-
ately before reaching the brow of the hill.
Make use of the vehicle's own impetus to
travel over the brow.
This style of driving prevents:
R the vehicle from lifting off the ground on the
brow of a hill
R the vehicle from travelling too quickly down
the other side
Driving downhill R
Drive slowly.
R Do not drive at an angle down steep
inclines. Steer into the line of fall and drive with the front wheels aligned straight. Oth-erwise, the vehicle could slip sideways, tip
and overturn.
R Before tackling steep downhill gradients,
use the left-hand steering wheel gearshift
paddle to shift to a lower gear.
R Activate DSR. If this is not sufficient, brake
gently. When doing so, make sure that the
vehicle is facing in the direction of the line
of fall.
R Check that the brakes are working normally
after a long downhill stretch. Off-road ABS is activated when the off-road
program is selected.
At speeds below 30 km/h the front wheels
lock cyclically during braking. The digging-in
effect achieved in the process reduces the
stopping distance when driving off-road. The
steerability of the vehicle is considerably
reduced if the wheels lock.
Driving systems
Mercedes-Benz Intelligent Drive
Mercedes-Benz Intelligent Drive stands for
innovative driver assistance and safety sys-
tems which enhance comfort and support the
driver in critical situations. With these intelli-
gent co-ordinated systems Mercedes-Benz
has set a milestone on the path towards
autonomous driving.
Mercedes-Benz Intelligent Drive embraces all elements of active and passive safety in one
well thought-out system – for the safety of the vehicle occupants and that of other road
users.
Further information on driving safety systems (Y page 78). Cruise control
General notes Cruise control maintains a constant road
speed for you. It brakes automatically in order to avoid exceeding the set speed. Change into
a lower gear in good time on long and steep
downhill gradients. Take particular note of
this when driving a laden vehicle and when
towing a trailer. 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 overheating and
wearing too quickly.
Use cruise control only if road and traffic con- ditions are appropriate for maintaining a
steady speed for a prolonged period. You canstore any road speed above 30 km/h. 230
Driving systemsDriving and parking

There are several ways to deactivate variable
SPEEDTRONIC:
X Briefly press the cruise control lever for-
wards =.
or X Briefly press the cruise control lever in the
direction of arrow ;.
LIM indicator lamp :in the cruise control
lever goes out. Variable SPEEDTRONIC is
deactivated.
Cruise control or DISTRONIC PLUS is selec-
ted.
i The last speed stored is cleared when you
switch off the engine.
Permanent SPEEDTRONIC
You can use the on-board computer to limit
the speed permanently to a value between
160 km/h(e.g. for driving on winter tyres) and the maximum speed (Y page 333).
Shortly before the stored speed is reached, it
appears in the multifunction display.
Permanent SPEEDTRONIC remains active,
even if variable SPEEDTRONIC is deactivated.
You cannot exceed the stored limit speed,
even if you depress the accelerator pedal
beyond the pressure point (kickdown). DISTRONIC PLUS
General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. Vehi-
cles are detected with the aid of the radar
sensor system. DISTRONIC PLUS brakes
automatically so that the set speed is not
exceeded.
Change into a lower gear in good time on long
and steep downhill gradients. Take particular note of this when driving a laden vehicle. 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 overheating and wearing too quickly.
If DISTRONIC PLUS detects that there is a risk
of a collision, you will be warned visually and acoustically. Without your intervention,
DISTRONIC PLUS cannot prevent a collision.
An intermittent warning tone will then sound
and the distance warning lamp will light up in
the instrument cluster. Brake immediately to
increase the distance to the vehicle driving in
front, or take evasive action, provided it is
safe to do so.
DISTRONIC PLUS operates in the range
between 0 km/h and 200 km/h.
Do not use DISTRONIC PLUS while driving on roads with steep gradients.
Important safety notes G
WARNING
DISTRONIC PLUS does not react to:
R people or animals
R stationary obstacles on the road, e.g. stop-
ped or parked vehicles
R oncoming and crossing traffic
As a result, DISTRONIC PLUS may neither give
warnings nor intervene in such situations.
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. G
WARNING
DISTRONIC PLUS cannot always clearly rec-
ognise other road users and complex traffic
conditions.
In such cases, DISTRONIC PLUS may:
R give an unnecessary warning and then
brake the vehicle
R neither give a warning nor intervene
R accelerate or brake unexpectedly
There is a risk of an accident.
Continue to drive carefully and be prepared to
brake, particularly if DISTRONIC PLUS warns
you. 236
Driving systemsDriving an
d parking

of the added maximum rear axle load when
towing a trailer, the vehicle/trailer combina-
tion may not exceed a maximum speed of
100 km/h for reasons concerning the oper-
ating permit. This also applies in countries in
which the permissible maximum speed for
vehicle/trailer combinations is above
100 km/h.
When towing a trailer, your vehicle's handling characteristics will be different in comparison
to when driving without a trailer and it will
consume more fuel.
Change into a lower gear in good time on long
and steep downhill gradients.
This also applies if cruise control, DISTRONIC PLUS or SPEEDTRONIC are activated.
This will use the braking effect of the engine,
so less braking will be required to maintain
vehicle speed. This relieves the load on the
brake system and prevents the brakes from
overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
Driving tips If the trailer swings from side to side:
X Do not accelerate.
X Do not countersteer.
X Brake if necessary.
R Maintain a greater distance to the vehicle in
front than when driving without a trailer.
R Avoid braking abruptly. If possible, brake
gently at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude. Swinging out the ball coupling
G
WARNING
If the ball coupling is not engaged, the trailer
may come loose. There is a risk of an accident.
Make sure that the ball coupling is securely
engaged and locked in position.
! Do not attempt to speed the up the swing-
out procedure by applying additional pres-
sure with your foot. The system could oth-
erwise be mechanically damaged.
In order to tow a trailer with your vehicle, you
must swing out the ball coupling using the
switch in the driver's door or in the tailgate.
The trailer power socket is integrated in the
ball coupling and swivels out with it.
Only release the ball coupling when its range of movement is unobstructed. Folding out using the switch in the driv-
er's door (all vehicles except plug-in
hybrid vehicles):
X Make sure that the vehicle is stationary.
X Shift the transmission to position P.
X Switch the ignition on.
X Pull switch :briefly.
After a short time the ball coupling swings
out from under the rear bumper. It can take
up to seven seconds before the ball cou-
pling visibly swings out.
X Remove the protective covering from the
ball coupling and store it in a safe place. 304
Towing a trailerDriving and parking

brightness will depend upon the brightness
of the ambient light.
i The light sensor in the instrument cluster
automatically controls the brightness of
the multifunction display.
In daylight, the displays in the instrument
cluster are illuminated. A dimming function
is not possible in daylight. Speedometer with segments
The speedometer is divided into segments on vehicles with DISTRONIC PLUS.
The segments in the speedometer indicate
which speed range is available.
R Cruise control activated (Y page 230):
The segments light up from the stored
speed to the type-tested maximum speed.
R Variable SPEEDTRONIC activated
(Y page 233):
The segments light up from the start of the
scale to the selected limit speed.
R DISTRONIC PLUS activated (Y page 236):
One or two segments in the set speed
range light up.
R DISTRONIC PLUS detects a vehicle in front
moving more slowly than the stored speed:
The segments between the speed of the
vehicle in front and the stored speed light
up. Rev counter
! Do not drive in the overrevving range.
Doing so will damage the engine.
The red band in the rev counter indicates the
engine's overrevving range.
The fuel supply is interrupted to protect the
engine when the red band is reached.
PLUG-IN HYBRID vehicles: when you select
the E-MODE operating mode, the display in
the instrument cluster switches from rev
counter to wattmeter (Y page 289). Outside temperature display
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
Bear in mind that the outside temperature
display indicates the measured air tempera-
ture and not the road surface temperature.
The outside temperature display is in the mul- tifunction display (Y page 315).
Changes in the outside temperature are dis-
played after a short delay. Coolant temperature gauge
G
WARNING
If you open the bonnet while the engine is
overheating or while there is a fire in the
engine compartment, you could come into
contact with hot gases or other leaking ser-
vice products. There is a danger of injury.
Allow an overheating engine to cool down
before opening the bonnet. If there is a fire in the engine compartment, leave the bonnet
closed and notify the fire brigade.
All vehicles except PLUG-IN HYBRID vehicles: the coolant temperature gauge is in the lower
section of the rev counter (Y page 34).
PLUG-IN HYBRID vehicles: the multifunction
display shows the coolant temperature in the
Coolant Coolant submenu (Y page 327).
At high outside temperatures and when driv-
ing uphill, the coolant temperature may rise
to the end of the scale.
Under normal operating conditions and with
the specified coolant level, the coolant tem-
perature may rise to 120 †. Displays and operation
313On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions ?
Coolant Stop vehi‐ Coolant Stop vehi‐
cle Switch engine cle Switch engine
off off The coolant is too hot.
A warning tone also sounds.
G WARNING
Never drive with an overheated engine. Driving when your engine is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
In addition, steam from an overheated engine can cause serious
burns, which can occur just by opening the bonnet.
There is a risk of injury.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 219).
X Wait until the engine has cooled down.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the display message goes out
and the coolant temperature is below 120 †. The engine may
otherwise be damaged.
X Pay attention to the coolant temperature display.
If the temperature increases again:
X Consult a qualified specialist workshop immediately.
Under normal operating conditions and with the specified coolant
level, the coolant temperature may rise to 120 †. #
See Owner's Manual See Owner's Manual The battery is not being charged.
A warning tone also sounds.
Possible causes:
R faulty alternator
R defective power electronics (PLUG-IN HYBRID vehicles)
R torn poly-V-belt
R a malfunction in the electronics
! Do not continue driving. The engine could otherwise overheat.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 219).
X Consult a qualified specialist workshop. 354
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Stop
Stop
vehicle
vehicle Leave
Leave
engine running
engine running
Wait Transmission Wait Transmission
cooling cooling The transmission has overheated. Pulling away can be temporarily
impaired or not possible.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Wait until the display message disappears before pulling away. Auxiliary battery
Auxiliary battery
malfunction malfunction PLUG-IN HYBRID vehicles only:
The auxiliary battery for the transmission is no longer being
charged.
X Consult a qualified specialist workshop.
X Until then, set the transmission to position Pbefore you switch
off the engine.
X Before leaving the vehicle, apply the electric parking brake. A The tailgate is open.
G WARNING
When the engine is running, exhaust gases can enter the vehicle
interior if the tailgate is open.
There is a risk of poisoning.
X Close the tailgate. ? The bonnet is open. A warning tone also sounds.
G WARNING
The open bonnet may then block your view when the vehicle is in
motion.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Safeguard the vehicle against rolling away (Y page 219).
X Close the bonnet. Active bonnet mal‐ Active bonnet mal‐
function See Own‐ function See Own‐
er's Manual er's Manual The active bonnet (pedestrian protection) is not active due to a
malfunction or because it has already been triggered.
X Consult a qualified specialist workshop. C C At least one door is open. A warning tone also sounds.
X Close all doors. Display
messages
371On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions ?
N
The red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked
or the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
X Observe the additional display messages in the multifunction display.
X Stop the vehicle immediately, paying attention to road and traffic condi-
tions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 219).
X Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and top up the coolant, observing the warning notes
(Y page 417).
X If you have to top up the coolant frequently, have the engine cooling system
checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
frozen slush.
X Do not start the engine again until the coolant temperature is below 120 †.
The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in mountainous
terrain and stop-start traffic. ?
N
The red coolant warning lamp comes on while the engine is running. A
warning tone also sounds.
The coolant temperature has exceeded 120 †. The airflow to the engine radi- ator may be blocked or the coolant level may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never drive with an overheated engine. Driving when your engine is overhea-
ted can cause some fluids which may have leaked into the engine compart-
ment to catch fire.
In addition, steam from an overheated engine can cause serious burns, which
can occur just by opening the bonnet.
There is a risk of injury.
X Observe the additional display messages in the multifunction display.
X Stop the vehicle immediately, paying attention to road and traffic condi-
tions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 219).Warning and indicator lamps in the instrument cluster
385On-board computer and displays Z

Useful information
i This Owner's Manual describes all mod-
els, series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos- sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 28). Engine compartment
Bonnet
Important safety notes G
WARNING
An unlocked bonnet may open up when the
vehicle is in motion and block your view. There is a risk of an accident.
Never unlock the bonnet when driving. Before
every trip, ensure that the bonnet is locked. G
WARNING
When being opened and closed, the bonnet
may suddenly fall into the closed position.
There is a risk of injury to persons in the range of movement of the bonnet.
Open and close the bonnet only when nobody
is in the range of movement. G
WARNING
If you open the bonnet while the engine is
overheating or while there is a fire in the
engine compartment, you could come into
contact with hot gases or other leaking ser-
vice products. There is a danger of injury.
Allow an overheating engine to cool down
before opening the bonnet. If there is a fire in the engine compartment, leave the bonnet
closed and notify the fire brigade. G
WARNING
There are moving components in the engine
compartment. Certain components may con-
tinue to move or suddenly move again even
after the ignition has been switched off, e.g.
the radiator fan. There is a risk of injury.
If you have to carry out work in the engine
compartment:
R switch off the ignition
R never touch the dangerous areas surround-
ing moving components, e.g. the rotation
area of the fan
R remove jewellery 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 operate with a high voltage. If you touch
the live components, you could receive an
electric shock. There is a danger of injury.
Never touch components of the ignition sys-
tem or the fuel injection system when the
ignition is switched on.
Active bonnet (pedestrian protection) Operating principle
! An active bonnet that had been triggered
must be repaired at a qualified specialist
workshop. The active bonnet function will
then be available again. The additional
pedestrian protection provided by the
active bonnet will then be restored.
The active bonnet is only available in certain
countries.
The active bonnet can reduce the risk of injury to pedestrians in certain accident situations.
Raising the active bonnet increases the clear-
ance to hard components, such as the engine.
If the active bonnet has been triggered, it is
raised at the rear in the area around the hinge
by approximately 85 mm. The active bonnet is
triggered by pyrotechnics. 414
Engine compartmentMaintenance and care