2015 MERCEDES-BENZ GLK-CLASS SUV maintenance

Useful information
iThis Operator's Manual describes all
models and all standard and optional equip- ment 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.
iRead the information on qualified special-
ist workshops ( Y page 27).
Overview of climate control systems
Important safety notes
Observe the settings recommended on the
following pages. The windows could other-
wise fog up.
To prevent the windows from fogging up:
R switch off climate control only briefly
R switch on air-recirculation mode only
briefly
R switch on the cooling with air dehumidifi-
cation function
R switch on the defrost windshield function
briefly, if required
Climate control regulates the temperature
and the humidity in the vehicle interior and
filters undesirable substances out of the air.
Climate control can only be operated when
the engine is running. Optimum operation is
only achieved with the side windows and roof
closed.
The residual heat function can only be acti-
vated or deactivated with the ignition
switched off ( Y page 143).
iVentilate the vehicle for a brief period
during warm weather, e.g. using the con-
venience opening feature ( Y page 93). This
will speed up the cooling process and the
desired interior temperature will be
reached more quickly.
iThe integrated filter filters out most par-
ticles of dust and soot and completely fil-
ters out pollen. It also reduces gaseous pol-
lutants and odors. A clogged filter reduces the amount of air supplied to the vehicle
interior. For this reason, you should alwaysobserve the interval for replacing the filter, which is specified in the Maintenance
Booklet. As it depends on environmental
conditions, e.g. heavy air pollution, the
interval may be shorter than stated in the
Maintenance Booklet.
iIt is possible that the dehumidification
function of the climate control system may
be activated automatically an hour after the
SmartKey has been removed. The vehicle is then ventilated for 30 minutes.
132Overview of climate control systems
Climate control

Problems with fuel and the fuel tank
ProblemPossible causes/consequences and M Solutions
Fuel is leaking from the
vehicle.The fuel line or the fuel tank is faulty.
GWARNING
Risk of explosion or fire.
X Turn the SmartKey to position 0 immediately and remove it
( Y page 149).
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop.
The engine does not
start.The fuel tank of a vehicle with a diesel engine has been run com-
pletely dry.
X Refuel the vehicle with at least 5.3 US qt (5 liters) of diesel.
X Turn the ignition on for approximately ten seconds
(Y page 149).
X Start the engine continuously for up to ten seconds unt il it runs
smoothly.
If the engine does not start: X Turn the ignition on again for approximately ten seconds
(Y page 149).
X Start the engine again continuously for up to ten seco nds until it
runs smoothly.
If the engine does not start after three attempts:
X Consult a qualified specialist workshop.
The fuel filler flap can-
not be opened.The fuel filler flap is not unlocked.
X Unlock the vehicle ( Y page 78).
The SmartKey battery is discharged or nearly discharged.
X Unlock the vehicle using the mechanical key ( Y page 80).
The fuel filler flap is unlocked, but the opening mecha nism is jam-
med.
X Consult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
Important notes on use
To function properly, BlueTEC exhaust gas
aftertreatment must be operated with the
reducing agent DEF. Adding DEF is one of the tasks performed during maintenance. Under
normal operating conditions, a tank of DEF
lasts until the next service due date.
When the supply of DEF is almost used up, theCheck Additive See Operator's Manual
Refueling165
Driving and parking
Z

message is shown in the multifunction dis-
play.
When the DEF supply drops to a minimum, the
Remaining Starts: 16 message is shown
in the multifunction display.
If the
Remaining Starts: 16 message
appears in the multifunction display, you can start the engine another 16 times. If DEF is
not refilled, you will subsequently be unable
to start the engine . Refill the DEF tank with
around 1 gal (3.8 l) of DEF or have the DEF
tank refilled at a qualified specialist work-
shop.
Use the special DEF refill bottle when adding DEF between maintenance intervals. Contact
a qualified specialist workshop with any ques-
tions or, if necessary, contact Roadside Assis- tance ( Y page 24).
If the outside temperature is below 12 ‡
( Ò 11 †) it may be difficult to top up. If DEF is
frozen and there is an active warning indica-
tor, it may not be possible to add DEF. Park
the vehicle in a warmer place, e.g. in a garage,
until DEF has become fluid again. It will then
be possible to add DEF again. Alternatively,
have the DEF tank refilled at a qualified spe-
cialist workshop.
Further information about BlueTEC exhaust
gas aftertreatment and DEF is available at any authorized Mercedes-Benz Center.
Important safety notes
DEF is a water-soluble fluid for the exhaust
gas aftertreatment of diesel engines. It is:
R not poisonous
R colorless and odorless
R not flammable
When you open the DEF container, small
amounts of ammonia vapor may be released. Ammonia vapors have a pungent odor and are
particularly irritating to the skin, to mucous
membranes and to the eyes. You may expe-
rience a burning sensation in your eyes, nose and throat. Coughing and watering of the
eyes are possible. Do not inhale ammonia vapors. Fill the DEF
tank only in well-ventilated areas.
DEF must not come into contact with your
skin, eyes or clothing and must not be swal-
lowed. Keep DEF away from children.
If you or other persons come into contact with
DEF, observe the following:
R Rinse DEF from your skin immediately with
soap and water.
R If DEF comes into contact with your eyes,
immediately rinse them thoroughly with
clean water. Seek medical assistance with-
out delay.
R If DEF has been swallowed, rinse your
mouth out immediately. Drink plenty of
water. Seek medical assistance without
delay.
R Change out of clothing contaminated with
DEF immediately.
! Only use DEF in accordance with
ISO 22241. Do not mix any additives with
DEF, and do not dilute DEF with water. This
may destroy the BlueTEC exhaust gas after- treatment system.
! Rinse surfaces that have come into con-
tact with DEF immediately with water or
remove DEF using a damp cloth and cold
water. If the DEF has already crystallized,
use a sponge and cold water to clean it. DEF
residues crystallize after time and contam-
inate the affected surfaces.
! DEF is not a fuel additive and must not be
added to the fuel tank. If DEF is added to
the fuel tank, this can lead to engine dam-
age.
! Only screw on the DEF refill bottle hand-
tight. It could otherwise be damaged.
The DEF filler neck is under the cargo com-
partment floor.
X Switch the ignition off.
X Open the tailgate.
X Lift up the cargo compartment floor
(Y page 314).
166Refueling
Driving and parking

traffic conditions. You could also lose controlof the vehicle. There is a risk of an accident.
Only operate this equipment when the vehicle is stationary.
Observe the legal requirements for the coun- try in which you are driving. Some jurisdic-
tions prohibit the driver from using a mobile
phone while driving a vehicle.
If you make a call while driving, always use
hands-free mode. Only operate the telephone when the traffic situation permits. If you are
unsure, pull over to a safe location and stop
before operating the telephone.
Bear in mind that at a speed of only 30 mph
(approximately 50 km/h), the vehicle covers
a distance of 44 ft (approximately 14 m) per
second.
Drive sensibly – save fuel
Observe the following tips to save fuel:
X The tires should always be inflated to the
recommended tire pressure.
X Remove unnecessary loads.
X Remove roof racks when they are not nee-
ded.
X Warm up the engine at low engine speeds.
X Avoid frequent acceleration or braking.
X Have all maintenance work carried out as
indicated by the service intervals in the
Maintenance Booklet or by the service
interval display.
Fuel consumption also increases when driv-
ing in cold weather, in stop-start traffic and in
hilly terrain.
Drinking and driving
GWARNING
Drinking and driving and/or taking drugs and driving are very dangerous combinations.
Even a small amount of alcohol or drugs can
affect your reflexes, perceptions and judg-
ment.
The possibility of a serious or even fatal acci-dent is greatly increased when you drink or
take drugs and drive.
Do not drink or take drugs and drive or allow
anyone to drive who has been drinking or tak-
ing drugs.
Emission control
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these exhaust gases leads to poisoning. There is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation.
Certain engine systems are designed to keep
the level of poisonous components in exhaust fumes within legal limits.
These systems only work at peak efficiency if they are serviced exactly in accordance with
the manufacturer's specifications. For this
reason, all work on the engine must be carried
out by qualified and authorized Mercedes-
Benz technicians.
The engine settings must not be changed
under any circumstances. Furthermore, all
specific service work must be carried out at
regular intervals and in accordance with the
Mercedes-Benz service requirements. Details can be found in the Maintenance Booklet.
ECO display
The ECO display provides feedback on how
economical your driving characteristics are.
The ECO display assists you in achieving the
most economical driving style for the selec-
ted settings and prevailing conditions. Your
driving style can significantly influence the
vehicle's consumption.
170Driving tips
Driving and parking

Braking
Important safety notes
GWARNING
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.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients
! On long and steep gradients, you must
reduce the load on the brakes by shifting
early to a lower gear. This allows you to take advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road sur-
face. This could cause damage to the drive train. This type of damage is not covered bythe Mercedes-Benz warranty.
Heavy and light loads
GWARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy load, do not stop the vehicle immediately.
Drive on for a short while. This allows the air-
flow to cool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rain without braking, there may be a delayed reac-
tion from the brakes when braking for the first time. This may also occur after the vehicle has
been washed.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehi- cle washed, brake firmly while paying atten-
tion to the traffic conditions. This will warm up
the brake discs, thereby drying them more
quickly and protecting them against corro-
sion.
Limited braking performance on salt-
treated roads
If you drive on salted roads, a layer of salt
residue may form on the brake discs and
brake pads. This can result in a significantly
longer braking distance. R Brake occasionally to remove any possible
salt residue. Make sure that you do not
endanger other road users when doing so.
R Carefully depress the brake pedal and the
beginning and end of a journey.
R Maintain a greater distance to the vehicle
ahead.
Servicing the brakes
! If the red brake warning lamp lights up in
the instrument cluster and you hear a warn-
ing tone while the engine is running, the
brake fluid level may be too low. Observe
additional warning messages in the multi-
function display.
The brake fluid level may be too low due to brake pad wear or leaking brake lines.
Have the brake system checked immedi-
ately. This work should be carried out at a
qualified specialist workshop.
All checks and maintenance work on the
brake system must be carried out at a quali-
172Driving tips
Driving and parking

Useful information............................300
Engine compartment ........................300
ASSYST PLUS .................................... 304
Care ................................................... .305
299
Maintenance and care

Useful information
iThis Operator's Manual describes all
models and all standard and optional equip- ment 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.
iRead the information on qualified special-
ist workshops ( Y page 27).
Engine compartment
Hood
Important safety notes
GWARNING
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. Before
every trip, ensure that the hood is locked.
GWARNING
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.
GWARNING
Opening the hood when the engine is over-
heated 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.
GWARNING
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 remove jewelry and watches
R keep items of clothing and hair, for exam-
ple, away from moving parts
GWARNING
The ignition system and the fuel injection sys-
tem 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 sys-
tem or fuel injection system when the ignition is switched on.
Opening the hood
GWARNING
Certain components in the engine compart-
ment, 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.
GWARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured bythe wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
300Engine compartment
Maintenance and care

! 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
turned off.
XPull release lever : on the hood.
The hood is released.
X Reach into the gap, pull hood catch han-
dle ; up and lift the hood.
If you lift the hood by approximately 15 in
(40 cm), the hood is opened and held open automatically by the gas-filled strut.
Closing the hood
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. Open it again and close
it with a little more force.
Engine oil
General notes on the oil level
Depending on your driving style, the vehicle
consumes up to 0.9 US qt (0.8 liters) of oil per
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.
Checking the oil level using the oil dip-
stick
GWARNING
Certain components in the engine compart-
ment, 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.
Example: vehicles with a gasoline engine
Engine compartment301
Maintenance and care
Z