cooling MERCEDES-BENZ C-CLASS SALOON 2014 User Guide

Problems with the "Cooling with air dehumidification" function
Problem
Possible causes/consequences and
M
MSolutions THERMOTRONIC
with auxiliary heat-
ing:
cooling with air
dehumidification can
no longer be switched
on using Audio 20/
COMAND Online; see
the separate operating
instructions. The cooling with air dehumidification function has been deactiva-
ted due to a malfunction.
X Visit a qualified specialist workshop. THERMATIC/
THERMOTRONIC
without auxiliary
heating:
the indicator
lamp in the ¿but-
ton flashes three times
or remains off. The
cooling with air dehu-
midification function
can also no longer be
activated using Audio
20/COMAND Online
(see the separate oper-
ating instructions). The cooling with air dehumidification function has been deactiva-
ted due to a malfunction.
X Visit a qualified specialist workshop. Setting climate control to automatic
mode
General notes In automatic mode, the set temperature is
maintained automatically at a constant level. The system automatically regulates the tem-
perature of the dispensed air, the airflow and
the air distribution.
The automatic mode functions optimally
when the "Cooling with air dehumidification"
function is activated. The "Cooling with air
dehumidification" function must be activated
manually in automatic mode. If necessary,
"Cooling with air dehumidification" can also
be deactivated.
If you deactivate the "Cooling with air-dehu-
midification" function, the air inside the vehi- cle will not be cooled. The air inside the vehi-
cle will also not be dehumidified. The win-
dows can mist up more quickly. Therefore,
only switch off cooling with air dehumidifica-
tion for a short period. Operating the climate control system
159Climate control

THERMATIC automatic climate control
with auxiliary heating
X Activate/deactivate the synchronisation
function using Audio 20/COMAND Online;
see the separate operating instructions).
The synchronisation function deactivates if
the settings for the front-passenger side are
changed.
THERMOTRONIC automatic climate con-
trol
X Activate/deactivate the synchronisation
function using Audio 20/COMAND Online;
see the separate operating instructions).
The synchronisation function is deactivated:
R if the settings for the front-passenger side
are changed
R if the settings for the rear compartment are
changed Demisting the windscreen
General notes You can use this function to defrost the wind-
screen or to demist the inside of the wind-
screen and the front side windows.
Switch off the windscreen demisting function as soon as the windscreen is clear again.
Activating/deactivating the wind-
screen demisting function X
Turn the key to position 2in the ignition
lock (Y page 181).
X To activate: press the¬rocker switch
on the front control unit up or down.
The indicator lamp above the ¬rocker
switch lights up. The current climate con-
trol settings are deactivated.
The climate control system switches to the
following functions:
R high airflow
R high temperature R
air distribution to the windscreen and
front side windows
R air-recirculation mode off
i If necessary, the "Cooling with air dehu-
midification" function is activated. In this
case, the indicator lamp above the
¿ button remains switched off.
X To deactivate: press the¬rocker
switch up or down.
The indicator lamp above the ¬rocker
switch goes out. The previous settings are
reactivated. Air-recirculation mode
remains deactivated.
or
X Press the top or bottom section of the Ã
rocker switch. Demisting the windows
Windows misted up on the inside X
Activate the "Cooling with air dehumidifi-
cation" function with the ¿rocker
switch.
or
X Activate the cooling with air dehumidifica-
tion function via Audio 20/COMAND
Online; see the separate operating instruc-
tions.
For THERMOTRONIC automatic climate
control with auxiliary heating, the "Cooling
with air dehumidification" function can only be activated using Audio 20/COMAND
Online.
X Switch on automatic mode using the Ã
rocker switch.
X If the windows continue to mist up, activate
the windscreen demisting function using
the ¬ rocker switch.
i You should only select this setting until
the windscreen is clear again. Operating the climate control system
163Climate control

Problems with the rear window heating
Problem
Possible causes/consequences and
M
MSolutions The rear window heat-
ing has switched off
prematurely or cannot
be activated. The battery has not been sufficiently charged.
X Switch off any consumers that are not required, e.g. reading
lamps, interior lighting or the seat heating.
When the battery is sufficiently charged, the rear window heat-
ing can be activated again. Activating/deactivating air-recircula-
tion mode
General notes You can also temporarily deactivate the flow
of fresh air manually if unpleasant odours are
entering the vehicle from outside. The air
already inside the vehicle will then be recir-
culated.
If you switch on air-recirculation mode, the
windows can mist up more quickly, in partic-
ular at low temperatures. Only use air-recir-
culation mode briefly to prevent the windows misting up.
Activating/deactivating X
Turn the key to position 2in the ignition
lock (Y page 181).
X To activate: press thegrocker switch
up or down.
The indicator lamp above the grocker
switch lights up.
Air-recirculation mode switches on automat-
ically:
R at high outside temperatures
R at high levels of pollution (THERMOTRONIC
automatic climate control only)
R in a tunnel (vehicles with a navigation sys-
tem only)
The indicator lamp above the grocker
switch is not lit when automatic air-recircula- tion mode is activated. Outside air is added
after about 30 minutes. X
To deactivate: press thegrocker
switch up or down.
The indicator lamp above the grocker
switch goes out.
Air-recirculation mode is deactivated auto-
matically:
R after approximately five minutes at outside
temperatures below approximately 5 †
R after approximately five minutes if cooling
with air dehumidification is deactivated
R after approximately 30 minutes at outside
temperatures above approximately 5 † if
the cooling with air dehumidification func-
tion is activated Convenience opening/closing using
the air-recirculation button G
WARNING
When the convenience closing feature is oper- ating, parts of the body could become trapped
in the closing area of the side window and the
sliding sunroof. There is a risk of injury.
Observe the complete closing procedure
when the convenience closing feature is oper-
ating. When closing make sure that no parts of the body are in the closing area. G
WARNING
During convenience opening parts of the body could be drawn in or become trapped
between the side window and window frame.
There is a risk of injury. Operating the climate control system
165Climate control
Z

X
To activate pre-entry climate control:
unlock the vehicle with the key or KEYLESS-
GO.
The air-conditioning functions are activatedfor up to 120 seconds for preheating and
for up to 60 seconds for pre-cooling.
The pre-entry climate control switches off
automatically when the engine is started.
Seat heating (heating), seat ventilation (ven-
tilation), perfume atomiser and ionisation
remain switched on after starting the engine. 170
Operating the climate control systemClimate control

Hybrid system overview
:
Recuperative Brake System
; 12 V battery
= High-voltage battery
? Electric cables for the high-voltage electrical system
A High-voltage battery cooling
B Electric refrigerant compressor
C Power electronics cooling
D Electric vacuum pump
E Transmission with electric motor
F Power electronics (DC/AC converter or DC/DC converter)
You can deactivate the hybrid system manually. For further information on the high-voltage
disconnect device, see (Y page 43). Hybrid operation
271Driving and parking Z

Engine
Display messages
Possible causes/consequences and
M
MSolutions +
Top Top
up
upcoolant
coolant See
See
Owner’s Manual
Owner’s Manual The coolant level is too low.
! Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Top up the coolant, observing the warning notes before doing so
(Y page 393).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ? ? The fan motor is faulty.
X If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid putting the engine under heavy load as you do so, e.g.
driving in mountainous terrain and stop-start traffic. ?
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 Secure the vehicle to prevent it from rolling away (Y page 207).
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.
X If the temperature increases again, visit a qualified specialist
workshop immediately.
Under normal operating conditions and with the specified coolant level, the coolant temperature may rise to 120 †. Display messages
333On-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 to prevent it from rolling away (Y page 207).
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 393).
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 putting the engine under heavy load 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 to prevent it from rolling away (Y page 207).Warning and indicator lamps in the instrument cluster
361On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions 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 393).
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 If the coolant temperature is below 120 †, you can continue driving to the
nearest qualified specialist workshop.
X Avoid putting the engine under heavy load as you do so, e.g. driving in
mountainous terrain and stop-start traffic. Hybrid system
Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions J
N
The yellow RBS (Recuperative Brake System) warning lamp is on. In addi-
tion, a warning tone may sound.
G Risk of accident
RBS is malfunctioning. The automatic engine switch-off function may also be deactivated.
X Observe the messages in the multifunction display (Y page 314).
X Drive on carefully.
X Visit a qualified specialist workshop. 362
Warning and indicator lamps in the instrument clusterOn-board computer and displays

G
WARNING
If engine oil comes into contact with hot com- ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Make sure that engine oil does not spill out
over the filler neck. Allow the engine to cool
down and thoroughly clean the components
that have come into contact with engine oil
before you start the engine. H
Environmental note
When topping up the oil, take care not to spill
any. If oil enters the soil or waterways, it is
harmful to the environment.
! Only use engine oils and oil filters that
have been approved for vehicles with a ser-
vice system. You can obtain a list of the
engine oils and oil filters tested and
approved in accordance with the
Mercedes-Benz Specifications for Service
Products at any Mercedes-Benz Service
Centre.
Damage to the engine or exhaust system is caused by the following:
R using engine oils and oil filters that have
not been specifically approved for the
service system
R changing the engine oil and oil filter after
missing the change interval required by
the service system
R using engine oil additives
! Do not add too much oil. Topping up with
too much engine oil can result in damage to
the engine or to the catalytic converter.
Have excess engine oil siphoned off. Example
X Turn cap :anti-clockwise and remove it.
X Top up the engine oil.
If the oil level is at or below the MIN mark on
the oil dipstick, top up with 1.0 lof engine
oil.
X Replace cap :on the filler neck and turn
clockwise.
Make sure that the cap locks securely into place.
X Check the oil level again with the oil dip-
stick (Y page 392).
For further information on engine oil, see
(Y page 473). Other service products
Checking the coolant level G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system.
There is a risk of injury when accessing the
engine compartment.
As far as possible, allow the engine to cool
down and only touch the components descri- bed in the following. G
WARNING
The engine cooling system is under pressure, particularly if the engine is warm. You could
be scalded by hot coolant spraying out when
opening the cap. There is a danger of injury. Engine compartment
393Maintenance and care
Z

Brake fluid
G
WARNING
The brake fluid continuously absorbs mois-
ture from the air. This results in the boiling
point of the brake fluid lowering. If the boiling
point of the brake fluid is too low, vapour
pockets may form when the brakes are sub-
jected to a heavy load. This would impair brak- ing efficiency. There is a risk of an accident.
Have the brake fluid renewed at the prescri-
bed intervals.
When handling brake fluid, observe the
important safety notes on service products
(Y page 468).
The brake fluid change intervals can be found in the Service Booklet.
Only use brake fluid approved by Mercedes-
Benz according to MB Approval 331.0.
Information about approved brake fluid can
be obtained at any qualified specialist work-
shop or on the Internet at
http://bevo.mercedes-benz.co m.
i Have the brake fluid regularly replaced at
a qualified specialist workshop and the
replacement confirmed in the Service
Booklet. Coolant
Important safety notes G
WARNING
If antifreeze comes into contact with hot com- ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Let the engine cool down before you top up
the antifreeze. Make sure that antifreeze is
not spilled next to the filler neck. Thoroughly
clean the antifreeze from components before
starting the engine.
! Only add coolant that has been premixed
with the desired antifreeze protection. You
could otherwise damage the engine. Further information on coolants can be
found in the Mercedes-Benz Specifications
for Service Products, MB Specifications for Service Products 310.1, e.g. on the Inter-
net at http://bevo.mercedes-benz.com.
Or contact a qualified specialist workshop.
! Always use a suitable coolant mixture,
even in countries where high temperatures prevail.
Otherwise, the engine cooling system is not
sufficiently protected from corrosion and
overheating.
i Have the coolant regularly replaced at a
qualified specialist workshop and the
replacement confirmed in the Service
Booklet.
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It is responsible
for the following:
R anti-corrosion protection
R antifreeze protection
R raising the boiling point
If antifreeze/corrosion inhibitor is present in
the correct concentration, the boiling point of
the coolant during operation will be approx-
imately 130 †.
The antifreeze/corrosion inhibitor concentra- tion in the engine cooling system should:
R be at least 50%. This will protect the engine
cooling system against freezing down to
approximately -37 †.
R not exceed 55% (antifreeze protection
down to -45 †). Heat will otherwise not be
dissipated as effectively.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in accord-
ance with
MB Specifications for Service Products 310.1
.
The coolant is checked at every maintenance interval at a qualified specialist workshop.
i When the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures Service products and capacities
475Technical data Z