engine overheat MERCEDES-BENZ CLS COUPE 2012 Owners Manual

There is
arisk of an accident.
Wear suitable footwear to ensure correct
usage of the pedals. G
WARNING
If you switch off the ignition while driving,
safety-relevan tfunctions are only available
wit hlimitations ,ornotat all. This could affect,
for example, the power steerin gand the brake
boosting effect .You will require considerably
more effort to steer and brake. There is arisk
of an accident.
Do not switch off the ignition while driving. G
WARNING
If the parking brake has not been fully
released when driving, the parking brake can:
R overheat and cause afire
R lose its hold function.
There is arisk of fire and an accident .Release
the parking brake fully before driving off.
! Warm up the engine quickly. Do not use
the engine' sfull performance until it has
reached operatin gtemperature.
Only set the automatic transmission to the
respective drive position swhen the vehicle
is stationary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. Otherwise, you could damage the
drive train.
! AMG vehicles: at low engine oil temper-
atures (below +20 †), the maximum
engine speed is restricted in order to pro-
tectt he engine. To protec tthe engine and
maintain smoot hengine operation ,avoid
driving at full throttle when the engine is
cold. Key positions
Key g
To remove the key
1 Power supply for some consumers, such
as the windscreen wipers
2 Ignition (power supply for all consumers)
and drive position
3 To start the engine
i If the key does not belong to the vehicle,
it can still be turned in the ignition lock.
However, the ignition will not be switched
on. The engine cannot be started.
KEYLESS-GO General notes
R
Do not keep the KEYLESS-GO key together
with:
-electronic devices, e.g. amobile phone
or another key
- metallic objects, e.g. coins or metal film
R Do not keep the KEYLESS-GO key together
in metallic objects, e.g. ametal case.
This can affect the functionality of KEY-
LESS-GO.
Vehicles with KEYLESS-GO are equipped with
ak ey featurin ganintegrated KEYLESS-GO
start function and adetachable Start/Stop
button.
The Start/Stop button must be inserted in the
ignition lock and the key must be in the vehi-
cle. Driving
141Driving and parking Z

i
This also applies if you have activated
cruise control, SPEEDTRONIC or DIS-
TRONIC PLUS.
This will use the braking effect of the engine,
so less braking will be required to prevent the
vehicle from gaining speed. This relieves the
load on the brake system and prevent sthe
brakes from overheatin gand wearing too
quickly.
Heavy and light loads G
WARNING
The braking system can overheat if you leave
your foot on the brake pedal while driving.
This increases the braking distanc eand could
even cause the braking system to fail. There
is ar isk of an accident.
Never use the brake pedal as afootrest. Do
not simultaneously depress both the brake
pedal and the accelerator pedal while driving.
! Depressin gthe brake pedal constantly
results in excessiv eand premature wear to
the brake pads.
If the brakes have been subjected to aheavy
load, do not stop the vehicle immediately, but
drive on for ashort while. This allows the air-
flow to cool the brakes more quickly.
If the brakes have been used only moderately,
you should occasionally test their effective-
ness. To do this, brake more firmly from a
higher speed. This improves the grip of the
brakes.
Wet road surfaces If you have driven for
along time in heavy rain
without braking, there may be adelayedr eac-
tion from the brakes when braking for the first
time. This may also occur after the vehicle has
been washed or driven through deep water.
You have to depress the brake pedal more
firmly. Maintain agreater distanc efrom the
vehicle in front.
After driving on awet 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,
alayer of salt
residue may form on the brake discs and
brake pads. This can result in asignificantly
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
beginnin gand end of ajourney.
R Maintain agreater distance to the vehicle
ahead.
New brake pads/linings New and replaced brake pads and discs only
reach their optimum braking effect after sev-
eral hundred kilometres of driving. Compen-
sate for this by applying greater force to the
brake pedal.
For safety reasons, Mercedes-Benz recom-
mends that you only have brake pads/linings
fitted to your vehicle which have been
approved for Mercedes-Benz vehicles or
which correspon dtoanequivalent quality
standard. Brake pads/linings which have not
been approved for Mercedes-Benz vehicles or
which are not of an equivalent quality could
affect your vehicle's operating safety.
AMG high-performance and ceramic
brakes The AMG brake systems are designed for
heavy loads. This may lead to noise when
braking. This is dependent on:
R
speed
R braking force
R environmental conditions, such as temper-
ature and humidity Driving tips
163Driving and parking Z

Slippery road surfaces
G
WARNING
If you shift down on aslippery road surface in
an attempt to increase the engine's braking
effect,t he drive wheels could lose their grip.
This increases the risk of skidding and having
an accident.
Do not shift down for additional engine brak-
ing on aslippery road surface.
If the vehicle threaten stoskid or cannot be
stopped when moving at low speed:
X Move the transmission to position N.
X Try to bring the vehicle under control by
using corrective steering.
You should drive particularly carefully on slip-
pery road surfaces. Avoid sudden accelera-
tion, steering and braking manoeuvres.
i For more information on driving with
snow chains, see (Y page 331). Driving systems
Cruise control
Important safety notes G
WARNING
Do not change down for additional engine
braking on aslippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid. G
WARNING
Cruise control cannot take account of road
and traffic conditions.
Always pay attention to traffic conditions
even when cruise control is activated.
Cruise control is only an aid designed to assist
driving. You are responsible for the vehicle's
speed and for braking in good time. G
WARNING
Do not use cruise control
R in traffic condition sthat do not allow you to
drive at aconstant speed (e.g. heavy traffic
or winding roads). You may otherwise
cause an accident.
R on slippery roads. The drive wheels may
lose their grip when braking or accelerating
and the vehicle may skid.
R when there is low visibility, e.g. due to fog,
heavy rain or snow.
General notes Cruise control maintains
aconstant road
speed for you. It brakes automatically in order
to avoid exceeding the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden, you must select shift range
1, 2or 3in good time. By doing so, you will
make use of the braking effect of the engine.
This relieves the load on the brake system and
preventst he brakes from overheating and
wearing too quickly.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a
steady speed for aprolonged period. You can
store any road speed above 30 km/h.
Cruise control lever :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed Driving systems
165Driving and parking Z

control off message in the multifunction
displayf or approximately five seconds.
i The last speed stored is cleared when you
switch off the engine. SPEEDTRONIC
Important safety notes G
WARNING
Never depress the brake pedal continuously
while the vehicle is in motion, e.g. never cause
the brakes to rub by applying constant slight
pedal pressure. This causes the brake system
to overheat, increases the braking distance
and can lead to the brakes failing completely. G
WARNING
Do not change down for additional engine
braking on aslippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid. G
WARNING
SPEEDTRONIC is only an aid designed to
assist driving. You are responsible for the
vehicle's speed and for braking in good time.
SPEEDTRONIC brakes automaticallysot hat
you do not exceed the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden, you must select shift range
1, 2or 3in good time. By doing so, you will
make use of the braking effect of the engine.
This relieves the load on the brake system and
prevents the brakes from overheating and
wearing too quickly. If you need additional
braking, depress the brake pedal repeatedly
rather than continuously.
You can set avariableorp ermanent limit
speed:
R variable for speed limits, e.g. in built-up
areas
R permanent for long-term speed restric-
tions, e.g. when driving with winter tyres
fitted (Y page 170) i
The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Variable SPEEDTRONIC General notes
:
To store the current speed or ahigher
speed
; LIM indicator lamp
= To store the current speed and call up the
last stored speed
? To store the current speed or alower
speed
A To switch between cruise control or DIS-
TRONIC PLUS and variableS PEEDTRONIC
B To deactivate variableS PEEDTRONIC
With the cruise control lever, you can operate
cruise control or DISTRONIC PLUS and vari-
able SPEEDTRONIC.
The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control or
DISTRONIC PLUS is selected.
R LIM indicator lamp on: variableSPEED-
TRONIC is selected.
Selecting variable SPEEDTRONIC G
WARNING
If there is achange of drivers, advise the new
driver of the limit speed stored.
Only use variableS PEEDTRONIC if you will not
have to accelerate suddenly to aspeed above 168
Driving systemsDriving and parking

G
WARNING
DISTRONIC PLUS cannot take account of road
and traffic conditions. If DISTRONIC does not
recognise or no longer recognise sthe vehicle
in front, do not activate DISTRONIC or, if it is
already active, deactivate it. This is especially
the case:
R before corners
R on filter lanes
R when changing to alane with faster moving
traffic
R in comple xdriving situations or where lanes
are diverted ,e.g. at roadworks on amotor-
way
DISTRONIC PLUS otherwise maintains the
current spee dset by you or accelerates up to
the set speed.
DISTRONIC PLUS cannot take account of
weather conditions. Deactivate, or do not
activate, DISTRONIC PLUS:
R if the road sare slippery ,snow-covered or
icy. The wheels could lose their grip when
braking or accelerating. The vehicl ecould
start to skid.
R if the sensors are dirty or there is poor vis-
ibility ,e.g. due to snow, rain or fog. Dis-
tance control may be impaired.
Always pay attention to traffic conditions
even when DISTRONIC PLUS is activated.
Otherwise, you may fail to recognise dangers
in time, caus eanaccident and injure yourself
and others. G
WARNING
DISTRONIC PLUS brakes yourv ehicle up to a
maximum of 4m/s2
depending on its speed.
This corresponds to approximately 40% of
your vehicle's maximum braking power. You
must also apply the brakes yourself if this
braking power is not sufficient.
If DISTRONIC PLUS detect sarisk of collision
with avehicle in front, an intermittent warning
tones ounds. In addition, the ·distance
warning lamp in the instrument cluster lights
up. Brak etoavoidacollision. General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tanc
etot he vehicle detected in front. DIS-
TRONIC PLUS brakes automatically so that
the set speed is not exceeded.
On long and steep downhill gradients, you
must select shift range 1,2or 3in good time.
By doing so, you will make use of the braking
effec tofthe engine. This relieves the load on
the brake system and prevents the brakes
from overheating and wearing too quickly.
If DISTRONIC PLUS detectsas lower-moving
vehicle in front,y our vehicle is braked in order
to maintain the preset distance to the vehicle
in front.
The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities (Y page 368).
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
(Y page 225) and operational.
If there is no vehicle in front,D ISTRONIC
PLUS operates in the same way as cruise
control in the speed range between
30 km/h and 200 km/h. If avehicle is driving
in fron tofyou, DISTRONIC operates in the
speed range between 0km/h and
200 km/h.
Do not use DISTRONIC PLUS on road swith
steep gradients. Driving systems
171Driving and parking Z

Display messages Possible causes/consequences and
M Solutions
?
Coolan
tStopv ehi‐ cle Switch engine
off The coolan
tistoo hot.
Aw arning tone also sounds.
G WARNING
Never driv ewithano verheate dengine. Drivin gwhen your engine
is overheate dcan caus esom efluids which may have leaked into
the engine compartmen ttocatch fire.
Steam fro manoverheated engine can caus eserious burns, which
can occur just by opening the bonnet.
This pose sarisk of injury.
X Stop the vehicl eimmediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicl eagainst rolling away (Y page159).
X Leave the vehicl eand keep asafe distance from the vehicl euntil
the engine has coole ddown.
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 display message goes out
and the coolant temperature is under 120 †. The engine may
otherwise be damaged.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visi taqualified specialist
workshop immediately.
The reading may rise up to 120 †undernormal driving conditions
if the coolant has been filled correctly. Display messages
241On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
# The battery is no
tbeing charged.
Aw arning tone also sounds.
Possible causes:
R fault yalternator
R torn poly-V-belt
R am alfunctio nintheelectronics
X Stop th evehicle immediately, payin gattentio ntoroad and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 159).
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
X Consult aqualified specialist workshop.
If the poly-V-belt is OK:
X Visit aqualified specialist workshop. 4
Check eng. oil
lev. when next
refuelling The engine oil level has dropped to the minimum level.
Aw
arning tone also sounds.
X Chec kthe oil level when next refuelling, at the latest
(Y page 298).
X If necessary, top up the engine oil (Y page 298).
X Have the engine checked at aqualified specialist workshop if
the engine oil needs topping up more often than usual. 4
Add
1 litre engine
oil when next refu‐
elling AMG vehicles: the engine oil level is too low.
X
Check the oil level when next refuelling, at the latest
(Y page 298).
X If necessary, top up the engine oil (Y page 298).
X Have the engine checked at aqualified specialist workshop if
the engine oil needs topping up more often than usual. 8
Reserve fuel level The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated when the fuel level
drops into the reserve range.
X
Refuel at the nearest filling station. 242
Display messagesOn-board computer and displays

Problem Possible 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 engine radiator
may be blocked or the electric engine radiator fan may be mal-
functioning.
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 Secure the vehicle against rolling away (Y page 159).
X Leave the vehicle and keep asafe 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 299).
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
under 120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine 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.
Awarning 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 compartmen ttocatch fire.
Steam from an overheated engine can cause serious burns, which
can occur just by opening the bonnet.
This poses arisk 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 Secure the vehicle against rolling away (Y page 159).268
Warning and indicator lampsint
he instrument clusterOn-board computer and displays

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 regularo il
changes using an approved engine oil with the
appropriate SA Eclassification. Brake fluid
G
WARNING
Over aperiod of time, the brak efluid absorbs
moisture fro mthe air; This lowers its boiling
point.
If the boiling point of the brake fluid is too low,
vapour pockets may form in the brake system
when the brakes are applied hard (e.g. when
driving downhill). This impairs braking effi-
ciency.
You should have the brake fluid renewed at
regular intervals. The brake fluid change inter-
vals can be found in the Service 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.
i Have the brake fluid renewed regularly at
aq ualified specialist workshop. Coolant
Important safety notes G
WARNING
Antifreeze is highly flammable. Fire, naked
flames and smoking are prohibited when han-
dling antifreeze.
If antifreeze comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any antifreeze on hot
engine parts. !
Only add coolant that has been premixed
with the desired antifreeze protection. You
could otherw ised amage 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 aqualified specialist workshop.
! Always use asuitable coolant mixture,
even in countries where high temperatures
prevail.
Otherwise, the engine cooling system is not
sufficiently protected from corrosio nand
overheating.
! The engine cooling system is filled with
coolant, which must be renewe dafter
15 years or after 250,000 kilometres at the
latest.
The coolant is amixture of water and anti-
freeze/corrosion inhibitor. It performs the
following tasks:
R anti-corrosio nprotection
R antifreeze protection
R raising the boiling point
If antifreeze/corrosion inhibitor is present in
the correct concentration, the boiling point of
the coolant during operation willbea pprox-
imatel y130 †.
The antifreeze/corrosion inhibitor concentra-
tion in the engine cooling system should:
R be at least 50%. Thi swillp rotect the engine
cooling system against freezing dow nto
approximately -3 7†.
R not exceed 55% (antifreeze protection
down to -45 †). Hea twill otherwise not be
dissipated as effectively.
If the vehicle has lost coolant, top it up with
equal amounts of water and antifreeze/cor-
rosio ninhibitor. Mercedes-Benz recom-
mend sana ntifreeze/corrosion inhibito rcon-
centrate in accordanc ewith MB Specifica-
tions for Servic eProducts 310.1. Service products and capacities
365Technical data Z