Engine MERCEDES-BENZ R-Class 2012 W251 Owner's Manual

XPull release lever : on the hood.
The hood is released.
! Make sure that the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield
wipers or the hood.
XReach into the gap, pull hood catch
handle ; up and lift the hood.
Once you have lifted the hood about
15 inches (40 cm), it is automatically
opened the rest of the way and held open
by the gas-filled struts.
Closing the hood
GWARNING
When closing the hood, use extreme caution
not to catch hands or fingers. Be careful that
you do not close the hood on anyone.
Make sure the hood is securely engaged
before driving off. Do not continue driving if
the hood can no longer engage after an
accident, for example. The hood could
otherwise come loose while the vehicle is in
motion and injure you and/or others.XLower the hood and let it fall from a height
of approximately 8 inches (20 cm).XCheck that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force.
Radiator
i Vehicles with a diesel engine: do not
cover the radiator, for example with a
winter front or bug cover. Otherwise, the
readings of the on-board-diagnostic
system may be inaccurate. Some of these
readings are required by law and must be
accurate at all times.
Engine oil
Notes on the oil level
Depending on the driving style, the vehicle
consumes up to 0.9 US qts. (0.8 l) of oil over
a distance of 600 miles (1000 km). The oil
consumption may be higher than this when
the vehicle is new or if you frequently drive at
high engine speeds.
Checking the oil level using the oil
dipstick
When checking the oil level:
R park the vehicle on a level surface.
R the engine should be switched off for
approximately five minutes if the engine is
at normal operating temperature.
Engine compartment283Maintenance and careZ

Example: gasoline engine
Example: diesel engine
XPull oil dipstick : out of the dipstick guide
tube.XWipe off oil dipstick :.XSlowly slide oil dipstick : into the guide
tube to the stop, and take it out again.
The oil level is correct if the level is between
MIN mark = and MAX mark ;.XAdd oil if necessary.
Adding engine oil
HEnvironmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
GWARNING
If engine oil comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any engine oil on hot
engine parts.
! Use only engine oils and oil filters that
have been approved for vehicles equipped
with a service system. A list of the engine
oils and oil filters tested and approved in
accordance with the Mercedes-Benz
Specifications for Service Products can be
called up by visiting http://
www.mbusa.com (USA only). More
information about tested and approved
engine oils and oil filters is available from
any authorized Mercedes-Benz Center.
Damage to the engine or exhaust system is
caused by the following:
R using engine oils and oil filters which
have not been specifically approved for
the service system.
R replacing the engine oil or oil filter after
the replacement interval required by the
service system has elapsed
R using engine oil additives.
Example: engine oil cap
XTurn cap : counter-clockwise and remove
it.XAdd the amount of oil required.
Fill carefully to the maximum mark on the oil
dipstick.
i Depending on the engine, the difference
in quantity between the MIN mark and the
MAX mark on the dipstick is approximately
1.6 to 2.1 US qt (1.5 to 2 l).
! Do not add too much oil. If the oil level is
above the "max" mark on the dipstick, too
much oil has been added. This can lead to
284Engine compartmentMaintenance and care

damage to the engine or the catalytic
converter. Have excess oil siphoned off.
For further information on engine oil, see
( Y page 358).XReplace cap : on the filler neck and
tighten clockwise.
Ensure that the cap locks into place
securely.
Checking and adding other service
products
Checking the coolant level
Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
XTurn the SmartKey to position
2 (Y page 145) in the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button twice ( Y page 145).XCheck the coolant temperature gauge in
the multifunction display.
The coolant temperature must be below
158 ‡ (70 †).GWARNING
In order to avoid any potentially serious burns:
R use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system, or
if the coolant temperature display indicates
that the coolant is overheated.
R do not remove the pressure cap on the
coolant reservoir if the coolant temperature
is above 158 ‡ (70 †). Allow the engine to
cool down before removing the cap. The
coolant reservoir contains hot fluid and is
under pressure.
R using a rag, slowly turn the cap
approximately 1
/ 2 turn to relieve excess
pressure. If opened immediately, scalding
hot fluid and steam will be blown out under
pressure.
R do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts.XSlowly turn cap : half a turn counter-
clockwise and allow excess pressure to
escape.XTurn cap : further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
= in the filler neck when cold, there is
enough coolant in coolant expansion
tank ;.
If the coolant is approximately 0.6 in
(1.5 cm) above marker bar = in the filler
neck when warm, there is enough coolant
in coolant expansion tank ;.XIf necessary, add coolant that has been
tested and approved by Mercedes-Benz.XReplace cap : and turn it clockwise as far
as it will go.
For further information on coolant, see
( Y page 359).
Windshield washer system and
headlamp cleaning system
The washer fluid reservoir is used for both the
windshield washer system and the headlamp
cleaning system.
i Vehicle components and their service
products must match. You should,
Engine compartment285Maintenance and careZ

therefore, only use products that have been
tested and approved by Mercedes-Benz.
Information on tested and approved
products can be obtained at any authorized
Mercedes-Benz Center or on the Internet at
http://www.mbusa.com (USA only).GWARNING
Washer solvent/antifreeze is highly
flammable. Do not spill washer solvent/
antifreeze on hot engine parts, because it may
ignite and burn. You could be seriously
burned.
! At temperatures below freezing: always
fill the washer fluid reservoir with a mix of
water and windshield washer concentrate
(e.g. MB WinterFit). There is otherwise a
risk of damaging the windshield washer
system/headlamp cleaning system.
! Only use washer fluid concentrate which
is suitable for plastic lenses. Unsuitable
washer fluid concentrate could damage the
plastic lenses of the headlamps.
! Do not add distilled or de-ionized water to
the washer fluid container. Otherwise, the
level sensor may be damaged.
i Add windshield washer concentrate, e.g.
MB SummerFit, to the washer fluid all year
round.
Example: washer fluid reservoir
XMix the windshield washer fluid in a
container beforehand.XAt temperatures above freezing: fill the
washer fluid reservoir with a mix of waterand windshield washer concentrate (e.g.
MB SummerFit).XAt temperatures below freezing: fill the
washer fluid reservoir with a mix of water
and windshield washer concentrate (e.g.
MB WinterFit). Adapt the mixing ratio to the
outside temperature. For information on
the mixing ratio ( Y page 360).XTo open: pull cap : upwards by the tab.XAdd the premixed washer fluid.XTo close: press cap : onto the filler neck
until it engages.
Brake fluid level
! If you notice that the brake fluid level in
the brake fluid reservoir has fallen to the
MIN mark or less, check the brake system
immediately for leaks. Also check the
thickness of the brake linings. Contact a
qualified specialist workshop, e.g. an
authorized Mercedes-Benz Center
immediately.
Do not add brake fluid. This does not
correct the error.
Only check the brake fluid level when the
vehicle is stationary and on a level surface.
The brake fluid level is correct if it is between
MIN marking ; and MAX marking : on the
brake fluid reservoir.
286Engine compartmentMaintenance and care

Maintenance
Service interval display
Service messages
Information on the type of service and service
intervals (see separate Service Booklet).
You can obtain further information from an
authorized Mercedes-Benz Center or at
http://www.mbusa.com (USA only).
The service interval display informs you of the
next service due date.
If a service due date has been exceeded, you
also hear an acoustic signal.
The multifunction display shows a service
message for a few seconds, e.g.
Service A in .. mi
Service A due now
Service A overdue by .. mi
The letter indicates how much time the
workshop will require to carry out the service
work. The letters displayed range from A for
a short service duration to H for a long service
duration.
The service interval display does not take into
account any periods of time during which the
battery is disconnected.
Maintaining the time-dependent service
schedule:
XNote down the service due date displayed
in the multifunction display before
disconnecting the battery.
or
XSubtract the battery disconnection periods
from the service date shown on the display
after reconnecting the battery.
i The service interval display does not
provide any information regarding the
engine's oil level. Observe the notes on the
engine oil level ( Y page 283).
Hiding a service messageXPress the . reset button on the
instrument cluster ( Y page 29).
Displaying a service message
XSwitch on the ignition.XPress V or U to select the standard
display menu on the steering wheel
( Y page 202).XSelect & or * to select the service
interval display.
The service due date appears in the
multifunction display.
Please bear the following in mind
Resetting service interval display
If the qualified specialist workshop, e.g. a
Mercedes-Benz Center, carried out the
maintenance work, the service interval
display will be reset.
Further information, on maintenance for
example, can be obtained at an authorized
Mercedes-Benz Center or directly from
Mercedes-Benz.
! If the service interval display has been
reset unintentionally, have the setting
corrected at a Mercedes-Benz Center.
Have service work carried out as described
in the Service Booklet. This may otherwise
lead to increased wear and damage to the
major assemblies or the vehicle.
Driving abroad
An extensive Mercedes-Benz Service network
is also available in other countries. You can
obtain further information from any
authorized Mercedes-Benz Center.
Care
Notes on care
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Care287Maintenance and careZ

Use care products and cleaning agents
recommended and approved by Mercedes-
Benz.GWARNING
Many cleaning products can be hazardous.
Some are poisonous, others are flammable.
Always follow the instructions on the
particular container. Always open your
vehicle's doors or windows when cleaning the
inside.
Never use fluids or solvents that are not
designed for cleaning your vehicle.
Always lock away cleaning products and keep
them out of reach of children.
! For cleaning your vehicle, do not use any
of the following:
R dry, rough or hard cloths
R abrasive cleaning agents
R solvents
R cleaning agents containing solvents
Do not scrub.
Do not touch the surfaces or protective
films with hard objects, e.g. a ring or ice
scraper. You could otherwise scratch or
damage the surfaces and protective film.
HEnvironmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible
manner.
! Do not park the vehicle for an extended
period straight after cleaning it, particularly
after having cleaned the wheels with wheel
cleaner. Wheel cleaners could cause
increased corrosion of the brake discs and
brake pads/linings. For this reason, you
should drive for a few minutes after
cleaning. Braking heats the brake discs and
the brake pads/linings, thus drying them.
The vehicle can then be parked.
Exterior care
Automatic car washGWARNING
Braking efficiency is reduced after washing
the vehicle. This could cause an accident. For
this reason, you must drive particularly
carefully after washing the vehicle until the
brakes have dried.
You can wash the vehicle in an automatic car
wash from the very start.
! Never clean your vehicle in a Touchless
Automatic Car Wash as these use special
cleaning agents. These cleaning agents can
damage the paintwork or plastic parts.
If the vehicle is very dirty, pre-wash it before
cleaning it in an automatic car wash.
! In car washes with a towing mechanism,
make sure that the automatic transmission
is in transmission position N, otherwise the
vehicle could be damaged.
R Vehicles with a SmartKey:
Do not remove the SmartKey from the
ignition lock. Do not open the driver's
door or front-passenger door when the
engine is switched off. Otherwise, the
automatic transmission selects park
position P automatically and locks the
wheels. You can prevent this by shifting
the automatic transmission to N
beforehand.
R Vehicles with KEYLESS-GO:
Do not open the driver's door or front-
passenger door when the engine is
switched off. Otherwise, the automatic
transmission selects park position P
automatically and locks the wheels.
Observe the following to make sure that the
automatic transmission stays in position N:
288CareMaintenance and care

Flat tire
Preparing the vehicle
Your vehicle may be equipped with a
collapsible spare wheel or MOExtended tires
(tires with run-flat properties) ( Y page 309).
i Vehicle preparation is not necessary on
vehicles with MOExtended tires.
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from an
authorized Mercedes-Benz Center.
XVehicles with the AIRMATIC package: make
sure that highway level is selected
( Y page 180).XStop the vehicle as far away as possible
from traffic on solid, non-slippery and level
ground.XSwitch on the hazard warning lamps.XFirmly depress the parking brake.XBring the front wheels into the straight-
ahead position.XMove the DIRECT SELECT lever to P.XSwitch off the engine.XVehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.XVehicles with KEYLESS-GO: open the
driver's door.
The on-board electronics have status 0,
which is the same as the SmartKey having
been removed.XVehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
( Y page 145).XAll occupants must get out of the vehicle.
Make sure that they are not endangered as
they do so.XMake sure that no one is near the danger
area while a wheel is being changed.Anyone who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.XGet out of the vehicle. Pay attention to
traffic conditions when doing so.XClose the driver's door.
i Only operate the tire inflation compressor
using the socket in the footwell of the
second row of seats ( Y page 268), even if
the ignition is turned off.
An emergency cut-off ensures that the on-
board electrical system voltage does not
drop too low. If the on-board electrical
system voltage is too low, power to the
sockets is automatically cut off. This
ensures that there is sufficient power to
start the engine.
TIREFIT kit
Using the TIREFIT kit
You can use the TIREFIT kit to seal small
punctures, particularly those in the tire tread.
You can use TIREFIT at outside temperatures
down to -4 ‡ (-20 †).
GWARNING
TIREFIT is a limited repair device. TIREFIT
cannot be used for cuts or punctures larger
than approximately 0.16 in (4 mm) and tire
damage caused by driving with extremely low
tire inflation pressure, or on a flat tire, or a
damaged wheel.
Do not drive the vehicle under such
circumstances.
Contact the nearest authorized Mercedes-
Benz Center for assistance or call Roadside
Assistance.
XDo not remove any foreign objects which
have penetrated the tire, e.g. screws or
nails.XRemove the tire sealant bottle, the
accompanying "max. 80 km/h" sticker and
the tire inflation compressor from theFlat tire299Breakdown assistanceZ

Securing the vehicle on level ground
XOn level ground: place chocks or other
suitable items under the front and rear of
the wheel that is diagonally opposite the
wheel you wish to change.
Securing the vehicle on slight downhill gradients
XOn downhill gradients: place chocks or
other suitable items in front of the wheels
of the front and rear axle.
Raising the vehicle
GWARNING
When jacking up the vehicle, only use the jack
which has been specifically approved by
Mercedes-Benz for your vehicle.
The jack is designed exclusively for jacking up
the vehicle at the jacking points built into both
sides of the vehicle. The jack saddle must be
placed centrally under the jacking point. The
jack must always be vertical when in use,
especially on inclines or declines.
The jack is intended only for lifting the vehicle
briefly for wheel changes. It is not suited for
performing maintenance work under the
vehicle. To help avoid personal injury, use the
jack only to lift the vehicle during a wheel
change.
Never get beneath the vehicle while it is
supported by the jack. Keep hands and feet
away from the area under the lifted vehicle.
Always lower the vehicle onto sufficient
capacity jackstands before working under the
vehicle.
Always firmly engage the parking brake and
block the wheels with wheel chocks or other
sizable objects before raising the vehicle with
the jack. Do not disengage the parking brake
while the vehicle is raised.
Make sure that the ground on which the
vehicle is standing and where you place the
jack is solid, level and not slippery. If
necessary, use a large underlay. On slippery
surfaces, such as tiled floors, you should use
a non-slip underlay, for example a rubber mat.
Do not use wooden blocks or similar objects
as a jack underlay. Otherwise, the jack may
not be able to achieve its load-bearing
capacity if it is not at its full height.
Never start the engine when the vehicle is
raised.
Also observe the notes on the jack.XUsing lug wrench :, loosen the bolts on
the wheel you wish to change by about one
full turn. Do not unscrew the bolts
completely.
The jacking points for the jack are located
behind the wheel housings of the front wheels
Flat tire305Breakdown assistanceZ

Wear suitable protective
clothing, in particular
gloves, an apron and a face
mask.
Immediately rinse acid
splashes off with clean
water. Consult a doctor if
necessary.Wear eye protection.Keep children away.Observe this Operator's
Manual.HEnvironmental noteBatteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.Dispose of batteries in an
environmentally friendly
manner. Return discharged
batteries to a qualified
specialist workshop, e.g. an
authorized Mercedes-Benz
Center, or to a special
collection point for old
batteries.GWARNING
Failure to follow these instructions can result
in severe injury or death.
Never lean over batteries while connecting.
You might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.GWARNING
Do not place any metal objects on the battery
as this could result in a short circuit.
Use leak-proof batteries only to avoid the risk
of acid burns in the event of an accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
! Before working on the battery, e.g.
loosening the battery terminals, switch off
the engine and remove the SmartKey from
the ignition. On vehicles with KEYLESS-GO,
make sure that the ignition is switched off.
Check that all the indicator lamps in the
instrument cluster are off. You may
otherwise destroy electronic components,
such as the alternator.
! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case have the battery
checked at a qualified specialist workshop,
such as an authorized Mercedes-Benz
Center. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact an authorized Mercedes-
Benz Center for more information.
Battery311Breakdown assistanceZ

The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Mercedes-Benz recommends that you do not
carry out work on batteries yourself, e.g.
removing or charging. Always have this work
performed at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.
i If the power supply has been interrupted,
e.g. if the battery has been reconnected,
you must carry out the following tasks:
R set the clock ( Y page 206).
On vehicles with COMAND and a
navigation system, the clock is set
automatically.
R reset the sliding sunroof ( Y page 90).
R reset the panorama roof with power tilt/
sliding panel ( Y page 92).
R reset the function for automatically
folding the exterior mirrors in/out by
folding the mirrors out once
( Y page 110).
R reset the side windows ( Y page 89).
Charging the battery
GWARNING
Never charge a battery still installed in the
vehicle unless a battery charger unit approved
by Mercedes-Benz is being used. Gases may
escape during charging and cause explosions
that may result in paint damage, corrosion or
personal injury.
A battery charger unit specially adapted for
Mercedes-Benz vehicles and tested and
approved by Mercedes-Benz is available as an
accessory. It permits the charging of the
battery in its installed position. Contact an
authorized Mercedes-Benz Center for further
information and availability.
Charge the battery in accordance with the
separate instructions for the battery charger.GWARNING
There is a risk of acid burns during the
charging process due to the gases which
escape from the battery. Do not lean over the
battery during the charging process.
GWARNING
Battery acid is caustic. Avoid contact with the
skin, eyes or clothing.
! Only charge the installed battery with a
battery charger which has been tested and
approved by Mercedes-Benz. These battery
chargers allow the battery to be charged
while still installed.
! Only use battery chargers with a
maximum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y page 313).
XOpen the hood ( Y page 282).XConnect the battery charger to the positive
terminal and earth point in the same order
as when connecting the donor battery in
the jump-starting procedure
( Y page 313).XRead the battery charger's operating
instructions before charging the battery.312BatteryBreakdown assistance