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Vehicle care213Vehicle checks
Performing work9 Warning
Only perform engine compartment
checks when the ignition is off.
The cooling fan may start
operating even if the ignition is off.
9 Danger
The ignition system uses
extremely high voltage. Do not
touch.
Bonnet
Opening
Open the driver's door.
Pull the release lever and return it to
its original position.
Push the safety catch upwards and
open the bonnet.
Secure the bonnet support.
Page 217 of 283
Vehicle care215Engine coolant
The factory filled coolant provides
freeze protection down to approx.
-37 °C.Caution
Only use approved antifreeze.
Coolant and antifreeze 3 254.
Coolant level
Caution
Too low a coolant level can cause engine damage.
If the cooling system is cold, the
coolant level should be above the
MIN mark. Top up if the level is low.
9Warning
Allow the engine to cool before
opening the cap. Carefully open
the cap, relieving the pressure
slowly.
To top up, use a 1:1 mixture of
released coolant concentrate mixed
with clean tap water. If no coolant
concentrate is available, use clean
tap water. Install the cap tightly. Have
the coolant concentration checked
and have the cause of the coolant
loss remedied by a workshop.
Washer fluid
Fill with clean water mixed with a
suitable quantity of approved
windscreen washer fluid which
contains antifreeze.
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216Vehicle careCaution
Only washer fluid with a sufficient
antifreeze concentration provides
protection at low temperatures or
a sudden drop in temperature.
Washer fluid 3 254.
Brakes In the event of minimum thickness of
the brake lining, a squealing noise
sounds during braking.
Continued driving is possible but
have the brake lining replaced as
soon as possible.
Once new brake linings are installed,
do not brake unnecessarily hard for
the first few journeys.
Brake fluid
9 Warning
Brake fluid is poisonous and
corrosive. Avoid contact with eyes,
skin, fabrics and painted surfaces.
The brake fluid level must be betweenthe DANGER and MAX marks.
If fluid level is below DANGER seek
the assistance of a workshop.
Brake and clutch fluid 3 254.
Vehicle battery
The vehicle battery is maintenance-
free provided that the driving profile
allows sufficient charging of the
battery. Short-distance-driving and
frequent engine starts can discharge
the battery. Avoid the use of
unnecessary electrical consumers.
Batteries do not belong in household
waste. They must be disposed of at
an appropriate recycling collection
point.
Laying up the vehicle for more than
four weeks can lead to battery
discharge. Disconnect the clamp from the negative terminal of the vehicle
battery.
Ensure the ignition is switched off
before connecting or disconnecting
the vehicle battery.
Battery discharge protection 3 121.
Replacing the vehicle battery Notice
Any deviation from the instructions
given in this section may lead to
temporary deactivation or
disturbance of the stop-start system.
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Vehicle care217When the vehicle battery is being
replaced, please ensure that there
are no open ventilation holes in the
vicinity of the positive terminal. If a
ventilation hole is open in this area, it
must be closed off with a dummy cap,
and the ventilation in the vicinity of the negative terminal must be opened.
Ensure that the battery is always replaced by the same type of battery.
The vehicle battery has to be
replaced by a workshop.
Stop-start system 3 138.
Charging the vehicle battery9 Warning
On vehicles with stop-start
system, ensure that the charging potential does not exceed 14.6 V
when using a battery charger.
Otherwise the vehicle battery may be damaged.
Jump starting 3 242.
Discharge protection
Battery voltage
When the vehicle battery voltage is
running low, a warning message will
appear in the Driver Information
Centre.
When the vehicle is being driven, the
load reduction function temporarily
deactivates certain functions, such as
the air conditioning, the heated rear
window, heated steering wheel, etc.
The deactivated functions are
reactivated automatically as soon as
conditions permit.
Idle boost
If charging of the vehicle battery is
required due to battery condition, the
power output of the generator must
be increased. This will be achieved by
an idle boost which may be audible.
A message appears in the Driver
Information Centre.
Power outlet
The power outlets are deactivated in
the event of low vehicle battery
voltage.Warning label
Meaning of symbols:
● No sparks, naked flames or smoking.
● Always shield eyes. Explosive gases can cause blindness or
injury.
● The vehicle battery contains sulphuric acid which could cause
blindness or serious burn
injuries.
● Keep the vehicle battery out of reach of children.
Page 233 of 283

Vehicle care231Directional tyresDirectional tyres should be mounted
so that they rotate in the correct
direction. The proper rotation
direction is indicated by a symbol (e.g. an arrow) on the sidewall.
Tyre pressure
Check the pressure of cold tyres at
least every 14 days and before any
long journey. Do not forget the spare
wheel. This also applies to vehicles
with tyre pressure monitoring system.
Tyre pressure 3 266.
The tyre pressure information label
on the left door frame indicates the
original equipment tyres and the
correspondent tyre pressures.
The tyre pressure data refers to cold
tyres. It applies to summer and winter tyres.
Always inflate the spare tyre to the
pressure specified for full load.
Incorrect tyre pressures will impair
safety, vehicle handling, comfort and
fuel economy and will increase tyre
wear.
Tyre pressures differ depending on
various options. For the correct tyre
pressure value, follow the procedure
below:
1. Identify the engine identifier code.
Engine data 3 260.
2. Identify the respective tyre.
The tyre pressure tables show all
possible tyre combinations 3 266.
For the tyres approved for your
vehicle, refer to the EEC Certificate of Conformity provided with your vehicle
or other national registration
documents.The driver is responsible for correct adjustment of tyre pressure.9 Warning
If the pressure is too low, this can
result in considerable tyre warm-
up and internal damage, leading to tread separation and even to tyre
blow-out at high speeds.
9 Warning
For specific tyres the
recommended tyre pressure as
shown in the tyre pressure table may exceed the maximum tyre
pressure as indicated on the tyre.
Never exceed the maximum tyre
pressure as indicated on the tyre.
Temperature dependency
The tyre pressure depends on the
temperature of the tyre. During
driving, tyre temperature and
pressure increase. Tyre pressure
values provided on the tyre
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232Vehicle careinformation label and tyre pressure
chart are valid for cold tyres, which means at 20 °C.
The pressure increases by nearly
1.5 psi for a 10 °C temperature
increase. This must be considered
when warm tyres are checked.
Tyre deflation detectionsystem
The tyre deflation detection system
continually checks the rotation speed
of all four wheels and warns on low
tyre pressure condition once vehicle
is driving. This is achieved by
comparing tyre rolling circumference
with reference values and further
signals.
If a tyre loses pressure the control
indicator w illuminates and a warning
message is displayed in the Driver
Information Centre.
In this case reduce speed, avoid
sharp cornering and strong braking.
Stop at next safe opportunity and
check tyre pressure.
Control indicator w 3 98.After adjusting tyre pressure initialise
system to extinguish the control
indicator and restart system.Caution
Deflation detection system warns
just about low tyre pressure
condition and does not replace
regular tyre maintenance by the
driver.
In case of a system malfunction a
message is displayed in the Driver
Information Centre. Set correct tyre
pressure and reinitialise system. If the
failure continues to be displayed,
contact a workshop. The system is
inoperable when ABS or ESC has a
malfunction or a temporary spare
wheel is used. Once the road tyre has
been refitted, check the tyre pressure with cold tyres and initialise the
system.
System initialisation
After tyre pressure correction or
wheel change, the system must be
initialised to learn new circumference reference values:
1. Always ensure that all four tyres have correct tyre pressure3 266.
2. Apply parking brake. 3. Press w to reset deflation
detection system.
4. Reset is confirmed by pop-up indication.
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Vehicle care233After initialisation system
automatically calibrates to new tyre
pressures during driving. After longer
drive the system will adopt and
monitor new pressures.
Always check tyre pressure with cold tyres.
System has to be reinitialised when: ● Tyre pressure has been changed
● Load condition has been changed
● Wheels have been swapped or exchanged
The system will not warn
instantaneously on a tyre blow out or a rapid deflation. This is due to
required calculation time.
Tread depthCheck tread depth at regular
intervals.
Tyres should be replaced for safety
reasons at a tread depth of 2-3 mm
(4 mm for winter tyres).For safety reasons, it is
recommended that the tread depth of
the tyres on one axle should not vary
by more than 2 mm.
The legally permissible minimum
tread depth (1.6 mm) has been
reached when the tread has worn
down as far as one of the tread wear
indicators (TWI). Their position is
indicated by markings on the
sidewall.
If there is more wear at the front than
the rear, swap round front wheels and rear wheels periodically. Ensure that
the direction of rotation of the wheels
remains the same.
Tyres age, even if they are not used.
We recommend tyre replacement
every 6 years.
Changing tyre and wheel
size
If tyres of a different size than those
fitted at the factory are used, it may be necessary to reprogramme the tyre
deflation detection system and make
other vehicle modifications.
Tyre deflation detection system
3 232.
Have the label with tyre pressures
replaced.9 Warning
The use of unsuitable tyres or
wheels may lead to accidents and will invalidate the vehicle
operating permit.
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234Vehicle careWheel coversWheel covers and tyres that are
factory approved for the respective
vehicle and comply with all of the
relevant wheel and tyre combination
requirements must be used.
If the wheel covers and tyres used are
not factory approved, the tyres must
not have a rim protection ridge.
Wheel covers must not impair brake
cooling.9 Warning
Use of unsuitable tyres or wheel
covers could lead to sudden
pressure loss and thereby
accidents.
Vehicles with steel wheels: When
using locking wheel nuts, do not
attach wheel covers.
Tyre chains
Tyre chains are only permitted on the
front wheels.
Always use fine mesh chains that add no more than 9 mm to the tyre tread
and the inboard sides (including chain
lock).
9 Warning
Damage may lead to tyre blowout.
Tyre chains are permitted on tyres of
size 215/70R16, 215/65 R17,
225/55 R18 and 205/55 R19.
Temporary spare wheel
The use of tyre chains is not permitted
on the temporary spare wheel.
Tyre repair kit
Minor damage to the tyre tread can be repaired with the tyre repair kit.
Do not remove foreign bodies from
the tyres.
Tyre damage exceeding 4 mm or that
is at tyre's sidewall cannot be repaired with the tyre repair kit.9 Warning
Do not drive faster than 50 mph.
Do not use for a lengthy period.
Steering and handling may be
affected.
In the case of a flat tyre:
Apply the parking brake and engage
first gear, reverse gear or P.