2012 MERCEDES-BENZ B-CLASS maintenance

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note
that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Read the information on qualified
specialist workshops: ( Y page 24).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. 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
Certain components in the engine
compartment, 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
Opening the hood when the engine is
overheated 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 keep clothing away from moving parts G
WARNING
The ignition system and the fuel injection
system 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
system or fuel injection system when the
ignition is switched on.
Opening the hood 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. 266
Engine compartment
Maintenance and care
ProCarManuals.com

!
Make sure that
the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield
wipers or the hood. X
Make sure that the windshield wipers are
switched off.
X Pull release lever : on the hood.
The hood is released. X
Reach into the gap between the hood and
the radiator trim and press hood catch
lever ; to the left.
X Raise the hood. X
Pull support strut ? out of bracket A.
X Lift up support strut ? and insert it into
yellow retaining clip =.
Closing the hood X
Raise the hood slightly and, at the same
time, remove support strut ? from yellow
retaining clip =.
X Swing support strut ? down and press it
into bracket A until it engages.
X Lower the hood and let it fall from a height
of approximately 8 in (20 cm).
X Check that

the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Do not press the hood
closed. Open the hood again and close it
with a little more force. Engine oil
General notes Depending on the driving style, the vehicle
consumes up to 0.9 US qt (0.8 liters) of oil
over a

distance of 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
approximately five minutes if the engine is
at normal operating temperature.
R if the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly: wait about 30 minutes
before carrying out the measurement. Engine compartment
267
Maintenance and care Z
ProCarManuals.com

Checking the oil level using the oil
dipstick
Example
X
Pull oil dipstick : out of the dipstick guide
tube.
X Wipe off oil dipstick :.
X Slowly slide oil dipstick : into the guide
tube to the stop, and take it out again.
If the level is between MIN mark = and
MAX mark ;, the oil level is correct.
X If the oil level has dropped to MIN mark
= or below, add 1.1 US qt
(1.0 liter) of
engine oil.
Adding engine oil G
WARNING
If engine oil comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Make sure that engine oil is not spilled next
to the filler neck. Let the engine cool down
and thoroughly clean the engine oil off the
components before starting the engine. H
Environmental note
When adding 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
service 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
center.
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 replacing engine oil and oil filters after
the interval for replacement specified by
the service system has been exceeded
R using engine oil additives.
! Do not add too much oil. adding too much
engine oil can result in damage to the
engine or to the catalytic converter. Have
excess engine oil siphoned off. Example: engine oil cap
X
Turn cap : counter-clockwise and remove
it.
X Add engine oil.
If the oil level is at or below the MIN mark
on the oil

dipstick, add 1.1 US qt (1.0 liter)
of engine oil.
X Replace cap : on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level again with the oil
dipstick (Y page 268).
Further information on engine oil
(Y page 332). 268
Engine compartment
Maintenance and care
ProCarManuals.com

Checking and adding other service
products
Checking coolant level G
WARNING
The engine cooling system is pressurized,
particularly when the engine is warm. When
opening the cap,
you could be scalded by hot
coolant spraying out. There is a risk of injury.
Let the engine cool down before opening the
cap. Wear eye and hand protection when
opening the cap. Open the cap slowly half a
turn to allow pressure to escape.
! The coolant may only be checked and
corrected when the engine is cool (coolant
temperature below 104 ‡ (40 †).
Checking the coolant when the coolant
temperature is above 104 ‡ (40 †) may
result in damage to the engine or to the
engine cooling system. Example
X
Park the vehicle on a level surface.
Only check the coolant level when the
vehicle is on

a level surface and the engine
has cooled down.
X Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X Check the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
104 ‡ (40 †).
X Turn the SmartKey to position
0 (

Y page 135) in the ignition lock. X
Slowly turn cap : half a turn counter-
clockwise to allow excess pressure to
escape.
X Turn 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 ;.
X If necessary, add coolant that has been
tested and approved by Mercedes-Benz.
X Replace cap : and turn

it clockwise as far
as it will go.
For further information on coolant, see
(Y page 333).
Adding washer fluid to the windshield
washer system/headlamp cleaning
system G
WARNING
Windshield washer concentrate is highly
flammable. If it comes into contact with hot
engine components or the exhaust system it
could ignite. There is a risk of fire and injury.
Make sure that no windshield washer
concentrate is spilled next to the filler neck. Example
X
To open: pull cap : upwards by the tab.
X Add the premixed washer fluid.
X To close:
press cap :
onto the filler neck
until it engages. Engine compartment
269
Maintenance and care Z
ProCarManuals.com

The washer fluid reservoir is used for both the
windshield washer
system
and the headlamp
cleaning system.
The recommended minimum amount when
topping up is 1 liter. If the water level drops
below this, a message appears in the
multifunction display prompting you to refill
the washer fluid ( Y page 223).
Further information on windshield washer
fluid/antifreeze ( Y page 334).Maintenance
ASSYST PLUS
Service messages The ASSYST PLUS service interval display
informs you of the next service due date.
Information on
the

type of service and service
intervals (see the separate Maintenance
Booklet).
You can obtain further information from an
authorized Mercedes-Benz Center or at
http://www.mbusa.com (USA only).
i The ASSYST PLUS service interval display
does not show any information on the
engine oil level. Observe the notes on the
engine oil level ( Y page 267).
The multifunction display shows a service
message for several seconds, e.g.:
R Next Service A in .. Days
R Service A Due
R Service A Exceeded by .. Days
Depending on the operating conditions of the
vehicle, the remaining time or distance until
the next service due date is displayed.
The letter A or B, possibly in connection with
a number or another letter, shows the type of
service. A stands for a minor service and B for
a major service.
You can obtain further information from an
authorized Mercedes-Benz Center.
The ASSYST PLUS service interval display
does not take into account any periods of time during which the battery is
disconnected.
Maintaining the time-dependent service
schedule:
X
Note down the service due date displayed
in the multifunction display before
disconnecting the battery.
or
X After reconnecting the battery, subtract
the battery
disconnection

periods from the
service date shown on the display.
Hiding a service message X
Press % or a.
Displaying service messages X
Switch on the ignition.
X Using = or ;, select the Serv.
menu.
X Press 9 or : to select the ASSYST
PLUS submenu and

press a to confirm.
The service due date appears in the
multifunction display.
Information about Service Resetting the ASSYST PLUS service
interval display
!
If the ASSYST PLUS service interval
display has been inadvertently reset, this
setting can be corrected at a qualified
specialist workshop.
Have service work

carried out as described
in the Maintenance Booklet. This may
otherwise lead to increased wear and
damage to the major assemblies or the
vehicle.
A qualified specialist workshop, e.g. an
authorized Mercedes-Benz Center, will reset
the ASSYST PLUS service interval display
after the service work has been carried out.
You can also obtain further information on
maintenance work, for example. 270
Maintenance
Maintenance and care
ProCarManuals.com

Special service requirements
The specified
maintenance
interval takes only
the normal operation of the vehicle into
account. Under arduous operating conditions
or increased load on the vehicle,
maintenance work must be carried out more
frequently, for example:
R regular city driving with frequent
intermediate stops
R if the vehicle is primarily used to travel
short distances
R use in mountainous terrain or on poor road
surfaces
R if the engine is often left idling for long
periods
Under these or similar conditions, have, for
example, the air filter, engine oil and oil filter
replaced or changed more frequently. Under
arduous operating conditions, the tires must
be checked more often. Further information
can be obtained at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center.
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
General notes
H
Environmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible
manner.
! 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.
! 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.
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Use care products and cleaning agents
recommended and approved by Mercedes-
Benz. Exterior care
Automatic car wash G
WARNING
Braking efficiency is reduced after washing
the vehicle. There is a risk of an accident.
After the vehicle has been washed, brake
carefully while paying attention to the traffic
conditions until full

braking power is restored.
! If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes
automatically in certain situations. To
prevent damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or other similar situations:
R when towing the vehicle
R in the car wash
! 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. Care
271
Maintenance and care Z
ProCarManuals.com

!
Make sure that the automatic
transmission is in
position N when washing
your vehicle in a tow-through car wash. The
vehicle could be damaged if the
transmission is in another position.
! Make sure that:
R the side windows and the sliding sunroof
are fully closed.
R the ventilation/heating is switched off
(the OFF button has been pressed/the
airflow control is set to position 0).
R the windshield wiper switch is in position
0.
Otherwise, the vehicle might be damaged.
You can wash the vehicle in an automatic car
wash from the very start.
If the vehicle is very dirty, pre-wash it before
cleaning it in an automatic car wash.
After using an automatic car wash, wipe off
wax from the windshield and the wiper
blades. This will prevent smears and reduce
wiping noises caused by residue on the
windshield.
Washing by hand In some countries, washing by hand is only
allowed at wash bays that are specially
designed for this purpose. Observe the legal
requirements in all countries concerned.
X
Do not use hot water and do not wash the
vehicle in direct sunlight.
X Use a soft sponge to clean.
X Use a mild cleaning agent, such as a car
shampoo approved by Mercedes-Benz.
X Thoroughly hose down the vehicle with a
gentle jet of water.
X Do not point the water jet directly towards
the air inlet.
X Use plenty of water and rinse out the
sponge frequently. X
Rinse the vehicle with clean water and dry
thoroughly with a chamois.
X Do not let the cleaning agent dry on the
paintwork.
When using the vehicle in winter, remove all
traces of road salt deposits carefully and as
soon as possible.
Power washers G
WARNING
The water jet from a circular jet nozzle (dirt
blasters) can cause

invisible exterior damage
to the tires or chassis components.
Components damaged in this way may fail
unexpectedly. There is a risk of an accident.
Do not use power washers with circular jet
nozzles to clean the vehicle. Have damaged
tires or chassis components replaced
immediately.
! Always maintain a distance of at least
11.8 in (30 cm) between the vehicle and the
power washer nozzle. Information about
the correct distance is available from the
equipment manufacturer.
Move the power washer nozzle around
when cleaning your vehicle.
Do not aim directly at any of the following:
R tires
R door gaps, roof gaps, joints, etc.
R electrical components
R battery
R connectors
R lights
R seals
R trim
R ventilation slots
Damaged seals or electrical components
can lead to leaks or failures. 272
Care
Maintenance and care
ProCarManuals.com

Cleaning the wheels
!
Do not use
acidic wheel cleaning products
to remove brake dust. This could damage
wheel bolts and brake components.
! 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.
Cleaning the paintwork !
Do not affix:
R stickers
R films
R magnetic plates or similar items
to painted surfaces. You could otherwise
damage the paintwork.
X Remove dirt immediately, where possible,
while avoiding rubbing too hard.
X Soak insect remains with insect remover
and rinse off the treated areas afterwards.
X Soak bird droppings with water and rinse
off the treated areas afterwards.
X Remove coolant, brake fluid, tree resin,
oils, fuels and greases by rubbing gently
with a cloth soaked in petroleum ether or
lighter fluid.
X Use tar remover to remove tar stains.
X Use silicone remover to remove wax.
X Use a suitable touch-up stick, e.g. MB
Touch-Up Stick, to repair slight damage to
the paintwork quickly and provisionally.
The following cannot always be completely
repaired:
R scratches
R corrosive deposits R
areas affected by corrosion
R damage caused by inadequate care
In such cases, visit a qualified specialist
workshop.
If water no

longer forms "beads" on the paint
surface, use the paint care products
recommended and approved by Mercedes-
Benz. This is the case approximately every
three to five months, depending on the
climate conditions and the care product used.
If the dirt has penetrated the paint surface or
if the paintwork has become dull, then the
paintwork should be cleaned. For cleaning,
please use the paint cleaner recommend and
approved by Mercedes Benz.
Do not use these care products in the sun or
on the hood while the hood is hot.
Matte finish care !
Never polish the vehicle or the light alloy
wheels. Polishing causes the finish to
shine.
! The following may cause the paint to
become shiny and thus reduce the matte
effect:
R Vigorous rubbing with unsuitable
materials.
R Frequent use of car washes.
R Washing the vehicle in direct sunlight.
! Never use paint cleaner, buffing or
polishing products, or

gloss preserver, e.g.
wax. These products are only suitable for
high-gloss surfaces. Their use on vehicles
with matte finish leads to considerable
surface damage (shiny, spotted areas).
Always have paintwork repairs carried out
at a qualified specialist workshop.
! Do not use wash programs with a hot wax
treatment under any circumstances.
Observe these notes if your vehicle has a
clear matte finish. This will help you to avoid
damage to the paintwork due to incorrect
treatment. Care
273
Maintenance and care Z
ProCarManuals.com