2015 MERCEDES-BENZ GLK-CLASS SUV engine overheat

ProblemPossible causes/consequences and M Solutions
?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.The coolant level is too low.
If the coolant level is correct, the airflow to the eng ine radiator may
be blocked or the electric engine radiator fan may be malfunc-
tioning.
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 Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 168).
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 snow, slush or ice.
X Check the coolant level and add coolant ( Y page 303). Observe
the warning notes.
X If you need to add coolant more often than usual, have the
engine coolant system checked.
X At coolant temperatures below 248 ‡ (120 †), drive to the
nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. drivin g in moun-
tainous terrain, and stop-and-go traffic.
?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.The coolant temperature has exceeded 248 ‡ (120 †). The air-
flow to the engine radiator may be blocked or the coo lant level may
be too low.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can ca use some
fluids which may have leaked into the engine compartment to
catch fire.
Steam from the overheated engine can also cause serious burns
which can occur just by opening the hood.
There is a risk of injury. X Observe the additional display messages in the multifunction
display.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 168).
X Wait until the engine has cooled down.
Warning and indicator lamps in the instrument cluster269
On-board computer and displays
Z

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

If standard unleaded gasoline is unavaila-
ble and you have to refuel with unleaded
gasoline of a lower grade, observe the fol-
lowing precautions: ROnly fill the fuel tank to half full with reg-
ular unleaded gasoline and fill the rest
with premium-grade unleaded gasoline
as soon as possible.
R Do not drive at the maximum speed.
R Avoid sudden acceleration and engine
speeds over 3,000 rpm.
You will usually find information about the fuel
grade on the pump. If you cannot find the
label on the pump, ask the staff for assis-
tance.
iFor further information, consult a quali-
fied specialist workshop or visit
http://www.mbusa.com (USA only).
iE10 fuel contains up to 10% bioethanol.
Your vehicle is E10-compatible. You can
refuel your vehicle using E10 fuel.
As a temporary measure, if the recommended fuel is not available, you may also use regularunleaded gasoline with an octane rating of
87 AKI/91 RON. This may reduce engine per-
formance and increase fuel consumption.
Avoid driving at full throttle and sudden accel- eration. Never refuel using fuel with a lower
AKI.
Information on refueling ( Y page 162).
Additives
! Operating the engine with fuel additives
added later can lead to engine failure. Do
not mix fuel additives with fuel. This does
not include additives for the removal and
prevention of residue buildup. gasoline
must only be mixed with additives recom-
mended by Mercedes-Benz. Comply with
the instructions for use on the product
label. More information about recommen-
ded additives can be obtained from any
authorized Mercedes-Benz Center.
Mercedes-Benz recommends that you use
branded fuels that have additives. The quality of the fuel available in some coun-
tries may not be sufficient. Residue could
build up in the injection system as a result. In
such cases, and in consultation with an
authorized Mercedes-Benz Center, the gaso-
line may be mixed with the cleaning additive
recommended by Mercedes-Benz. You must
observe the notes and mixing ratios specified on the container.
Diesel
Fuel grade
GWARNING
If you mix diesel fuel with gasoline, the flash
point is lower than that of pure diesel fuel.
When the engine is running, exhaust system
components could overheat without being
noticed. There is a risk of fire.
Never refuel with gasoline. Never mix gasoline with diesel fuel.
! Only use commercially available vehicular
ULTRA-LOW SULFUR DIESEL FUEL (ULSD,
15 ppm maximum sulfur content) that
meets the ASTM D975 standard. If you do
not refuel with ULSD, you may damage the
BlueTEC exhaust gas aftertreatment sys-
tem of the vehicle.
! Do not use gasoline to refuel vehicles with
a diesel engine. Do not mix diesel fuel with
gasoline, kerosene or paraffin. This may
otherwise result in damage to the fuel sys- tem and engine.
You will usually find information about the fuel grade on the pump. If you cannot find the
label on the pump, ask the staff for assis-
tance.
iFor further information, consult a quali-
fied specialist workshop or visit
http://www.mbusa.com (USA only).
Information on refueling ( Y page 162).
Service products and filling capacities375
Technical data
Z

When handling brake fluid, observe the
important safety notes on service products
(Y page 373).
The brake fluid change intervals can be found in the Maintenance 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.com.
iHave the brake fluid regularly replaced at
a qualified specialist workshop and the
replacement confirmed in the Maintenance
Booklet.
Coolant
Important safety notes
GWARNING
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 add anti-
freeze. 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 BeVo 310.1, e.g.
on the Internet at
http://bevo.mercedes-benz.com. Or con-
tact 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.
iHave the coolant regularly replaced at a
qualified specialist workshop and the
replacement confirmed in the Maintenance Booklet.
Comply with the important safety precautions
for service products when handling coolant
( Y page 373).
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It performs the
following tasks:
R corrosion protection
R antifreeze protection
R raising the boiling point
If the coolant has antifreeze protection down to -35 ‡ (-37 †), the boiling point of the cool-
ant during operation is approximately 266 ‡
(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 -35 ‡ (-37 †).
R not exceed 55% (antifreeze protection
down to -49 ‡ [-45 †]). Otherwise, heat
will not be dissipated as effectively.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in accord-
ance with MB Specifications for Service Prod-
ucts 310.1.
iWhen the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures
adequate antifreeze and corrosion protec-
tion.
iThe coolant is checked with every main-
tenance interval at a qualified specialist
workshop.
378Service products and filling capacities
Technical data