engine overheat MERCEDES-BENZ A-CLASS HATCHBACK 2015 User Guide

Display messages
Possible causes/consequences and
M
MSolutions Stop
Stop
vehicle
vehicle Shift
Shift
to P Leave engine
to P Leave engine
running running The automatic transmission has overheated.
X Drive on carefully.
If the display message disappears, the automatic transmission
is available again.
If the multifunction display still shows the display message:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Safeguard the vehicle against rolling away (Y page 184).
X Wait until the automatic transmission has cooled down and the
display message goes out. Auxiliary battery Auxiliary battery
malfunction malfunction The auxiliary battery for the automatic transmission is no longer
being charged.
X Consult a qualified specialist workshop.
X Until then, set the transmission to position Pbefore you switch
off the engine.
X Before leaving the vehicle, apply the electric parking brake. Clutch overheated
Clutch overheated
Avoid Avoid
pulling
pulling away
away
If necessary,
If necessary,
quickly release quickly release
and engage the and engage the
clutch clutch The clutch is under considerable load and the permitted operating
temperature has been exceeded. A warning tone also sounds.
Avoid frequent pulling away and driving at walking pace over lon-
ger distances.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Safeguard the vehicle against rolling away (Y page 184).
X Leave the engine running.
The clutch is cooled more quickly with the engine running.
or X If possible, continue driving at a steady speed.
X Remove your foot from the clutch pedal and do not allow the
clutch to slip.
The clutch may also cool down during the journey.
It may take several minutes for it to cool down. When the clutch
has cooled down, the display message disappears. The clutch is
fully operational again. For engine start For engine start
depress clutch depress clutch You have attempted to start the engine without depressing the
clutch pedal.
X Fully depress the clutch pedal.
X Restart the engine. Display
messages
287On-board computer/Displays Z

Display messages
Possible causes/consequences and
M
MSolutions The engine has stalled while pulling away, e.g. because the clutch
pedal was released too quickly.
X Depress the clutch pedal again.
The engine starts automatically.
X Slowly release the clutch pedal to pull away. Trans. Trans.
oil
oiloverhea‐
overhea‐
ted Drive on with
ted Drive on with
care care Mercedes-AMG vehicles: the transmission oil has overheated.
Manual drive program
Mand the temporarily active manual drive
program are no longer available. Engine power output is reduced.
X Allow the vehicle to cool down. 4matic currently 4matic currently
unavailable unavailable 4MATIC has overheated. The vehicle is only driven by the front
wheels.
X Drive on.
The airflow cools 4MATIC more quickly.
When the display message goes out, 4MATIC is available again
and the vehicle is driven by all four wheels. 4matic inoperative 4matic inoperative 4MATIC is malfunctioning. The vehicle is only driven by the front
wheels.
X Consult a qualified specialist workshop. A The tailgate is open.
G WARNING
When the engine is running, exhaust gases can enter the vehicle
interior if the tailgate is open.
There is a risk of poisoning.
X Close the tailgate. ? The bonnet is open.
A warning tone also sounds.
G WARNING
The open bonnet may then block your view when the vehicle is in
motion.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Safeguard the vehicle against rolling away (Y page 184).
X Close the bonnet. 288
Display
messagesOn-board computer/Displays

Problem
Possible causes/consequences and
M
MSolutions ?
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 engine 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 Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 184).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant, observing the
warning notes (Y page 326).
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the coolant temperature is
below 120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid putting the engine under heavy load as you do so, e.g.
driving in mountainous terrain and stop-start 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 120 †. The airflow to the
engine radiator may be blocked or the coolant level may be too
low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never drive with an overheated engine. Driving when your engine is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
In addition, steam from an overheated engine can cause serious
burns, which can occur just by opening the bonnet.
There is a risk of injury.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 184).302
Warning and indicator lamps in the instrument clusterOn-board computer/Displays

Useful information
i This Owner's Manual describes all mod-
els, series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos- sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 24). Engine compartment
Bonnet
Important safety notes G
WARNING
An unlocked bonnet may open up when the
vehicle is in motion and block your view. There is a risk of an accident.
Never unlock the bonnet when driving. Before
every trip, ensure that the bonnet is locked. G
WARNING
When being opened and closed, the bonnet
may suddenly fall into the closed position.
There is a risk of injury to persons in the range of movement of the bonnet.
Open and close the bonnet only when nobody
is in the range of movement. G
WARNING
If you open the bonnet while the engine is
overheating or while there is a fire in the
engine compartment, you could come into
contact with hot gases or other leaking ser-
vice products. There is a danger of injury.
Allow an overheating engine to cool down
before opening the bonnet. If there is a fire in the engine compartment, leave the bonnet
closed and notify the fire brigade. G
WARNING
There are moving components in the engine
compartment. Certain components may con-
tinue to move or suddenly move again even
after the ignition has been switched off, e.g.
the radiator fan. There is a risk of injury.
If you have to carry out work in the engine
compartment:
R switch off the ignition
R never touch the dangerous areas surround-
ing moving components, e.g. the rotation
area of the fan
R remove jewellery and watches
R keep items of clothing and hair, for exam-
ple, away from moving parts. G
WARNING
The ignition system and the fuel injection sys- tem operate with a high voltage. If you touch
the live components, you could receive an
electric shock. There is a danger of injury.
Never touch components of the ignition sys-
tem or the fuel injection system when the
ignition is switched on.
Active bonnet (pedestrian protection) Operating principle
! An active bonnet that had been triggered
must be repaired at a qualified specialist
workshop. The active bonnet function will
then be available again. The additional
pedestrian protection provided by the
active bonnet will then be restored.
The active bonnet is only available in certain
countries.
The active bonnet can reduce the risk of injury to pedestrians in certain accident situations.
Raising the active bonnet increases the clear-
ance to hard components, such as the engine.
If the active bonnet has been triggered, it is
raised at the rear in the area around the hinge
by approximately 60 mm.
For the drive to the workshop, reset the trig-
gered active bonnet yourself. If the active 322
Engine compartmentMaintenance and care

Engine oil viscosity
Viscosity describes the flow characteristics
of a fluid. If an engine oil has a high viscosity
rating, it flows slowly; the lower the viscosity,
the faster it flows.
Engine oil selection is based on the respective outside temperatures and in accordance with
the SAE classification (viscosity). The table
shows you which SAE classifications are to be
used. The low-temperature properties of
engine oils can be significantly impaired dur-
ing operation due to, for example, ageing or
soot and fuel accretion. It is therefore
strongly recommended to observe regular oil changes using an approved engine oil with the
appropriate SAE classification. Brake fluid
G
WARNING
The brake fluid continuously absorbs mois-
ture from the air. This results in the boiling
point of the brake fluid lowering. If the boiling
point of the brake fluid is too low, vapour
pockets may form when the brakes are sub-
jected to a heavy load. This would impair brak- ing efficiency. There is a risk of an accident.
Have the brake fluid renewed at the prescri-
bed intervals.
When handling brake fluid, observe the
important safety notes on service products
(Y page 396).
The brake fluid change intervals can be found in the Service Booklet. Only use brake fluid approved by Mercedes-
Benz according to MB-Freigabe or 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.
i Have the brake fluid regularly replaced at
a qualified specialist workshop and the
replacement confirmed in the Service
Booklet. Coolant
Important safety notes G
WARNING
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 top up
the antifreeze. 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 Specifications for Service Products 310.1, e.g. on the Inter-
net at http://bevo.mercedes-benz.com.
Or contact 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.
i Have the coolant regularly replaced at a
qualified specialist workshop and the
replacement confirmed in the Service
Booklet. 402
Service products and capacitiesTechnical data