2011 MERCEDES-BENZ C-CLASS SALOON engine overheat

on vehicles with automatic transmission,
select shift range
1,2or 3.
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 maintain
the speed. This relieves the load on the brake
system and prevents the brakes from over-
heating and wearing too quickly.
Heavy and light loads 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.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short 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 surface If driving in heavy rain for a prolonged period
of time without braking, there may be a
delayed reaction from the brakes when brak-
ing 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 G
WARNING
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly lon-
ger braking distance, which could lead to an
accident.
To avoid this danger, you should:
R occasionally brake carefully, without put-
ting other road users at risk, when you are
driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip, so that salt residues are removed
from the brake discs.
New brake pads/linings G
WARNING
New brake pads/linings only reach their opti-
mum braking effect after several hundred kil-
ometres of driving. Before this optimum brak-
ing effect is reached, you should compensate
for the reduced braking effect by applying
greater pressure when braking. This also
applies after the brake discs or the brake
pads/linings have been replaced.
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 correspond to an equivalent 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. 176
Driving tipsDriving and parking

At the onse
tofwinter, have your vehicle win-
terproofed at a qualified specialist workshop,
e.g. at a Mercedes-Benz Service Centre.
Observe the notes in the "Winter operation"
section (Y page 359).
Driving with summer tyres Observe the notes in the "Winter operation"
section (Y
page 359).
Slippery road surfaces G
WARNING
Do not shift down for additional engine brak-
ing on a slippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid.
You should drive particularly carefully on slip-
pery road surfaces. Avoid sudden accelera-
tion, steering and braking manoeuvres.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X Vehicles with manual transmission :engage
neutral.
X Vehicles with automatic transmission: shift
the transmission to position N.
X Try to bring the vehicl eunde rcontrol by
using corrective steering.
i For more information on driving with
snow chains, see (Y page 360).Driving systems
Cruise control
Important safety notes Cruise control maintains a constant road
speed for you. It brakes automatically in order
to avoid exceeding the set speed. You must
select a low gear in good time on long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer. On vehicles
with automatic transmission, select shift
range 1,2or 3.B y 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. G
WARNING
Do not change down for additional engine
braking on a slippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a
steady speed for a prolonged period. You can
store any road speed above 30 km/h. 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 conditions that do not allow you to
drive at a constant 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.
Cruise control lever You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.178
Driving systemsDriving and parking

Setting
aspeed X
Press the cruise control lever up :for a
highe rspeed or down ?for a lower speed.
X Keep the cruise control lever pressed until
the desired speed is reached.
X Release the cruise control lever.
The new speed is stored.
i Cruise control is not deactivated if you
depress the accelerator pedal. For exam-
ple, if you accelerate briefly to overtake,
cruise control adjusts the vehicle's speed
to the last speed stored after you have fin-
ished overtaking.
Making adjustments in 1 km/h incre-
ments X
Briefly press the cruise control lever to the
pressure point, up :for a higher speed or
down ?for a lower speed.
The last speed stored is increased or
reduced.
Making adjustments in 10 km/h incre-
ments X
Briefly press the cruise control lever
beyond the pressure point, up :for a
higher speed or down ?for a lower speed.
The last speed stored is increased or
reduced.
Deactivating cruise control There are several ways to deactivate cruise
control:
X Briefly press the cruise control lever for-
wards B.
or
X Brake or
X
Briefly press the cruise control lever in the
direction of arrow A.
Variable SPEEDTRONIC is selected. LIM
indicator lamp ;in the cruise contro llever
lights up.
Cruise control is automatically deactivated if:
R you depress the parking brake.
R you are driving at less than 30 km/h.
R ESP ®
intervenes or if you deactivate ESP ®
.
R you shift into neutral in a vehicle with man-
ual transmission while driving or depress
the clutch pedal for longer than six sec-
onds.
R on vehicles with manual transmission, you
shift to a gear that is too high, and as a
result the engine speed is too low.
R on vehicles with automatic transmission,
you shift into position Nwhile driving.
If cruise control is deactivated, you will hear
a warning tone. You will see the Cruise control off message in the multifunction
display for approximately five seconds.
i The last speed stored is cleared when you
switch off the engine. SPEEDTRONIC
Important safety notes SPEEDTRONIC brakes automatically so that
you do not exceed the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer, you must
shift to a lower gear in good time or select
shift range 1,2or 3on vehicles with auto-
matic transmission .By doing so, you will
make use of the brakin geffect of the engine,
which relieves the load on the brake system
and prevents the brakes from overheating
and wearing too quickly. If you need addi-
tional braking, depress the brake pedal
repeatedly rather than continuously. 180
Driving systemsDriving and parking

G
WARNING
Never depress the brake peda lcontinuously
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 a slippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid.
You can set a variable or permanent 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 183) 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.
i The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Variable SPEEDTRONIC General notes
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: variable SPEED-
TRONIC is selected. You can use the cruise control lever to limit
the speed to any speed above 30 km/hw
hile
the engine is running. :
To store the current speed or a higher
speed
; LIM indicator lamp
= To store the current speed or to call up
the last stored speed
? To store the current speed or a lower
speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate variable SPEEDTRONIC
Selecting variable SPEEDTRONIC
X Check whether LIM indicator lamp ;is on.
If it is on, variable SPEEDTRONIC is already
selected.
If it is not, press the cruise control lever in
the direction of arrow A.
LIM indicator lamp ;in the cruise control
lever lights up. Variable SPEEDTRONIC is
selected. G
WARNING
If there is a change of drivers, advise the new
driver of the limit speed stored.
Only use variable SPEEDTRONIC if you will not
have to accelerate suddenly to a speed above
that stored as the limit speed. You could oth-
erwise cause an accident. Driving systems
181Driving and parking
Z

You will hear a warning tone if this is the
case.
R on vehicles with manual transmission, if
you shift to a higher gear and as a result the
engine speed is too low. G
WARNING
It is not possible to deactivate variable Speed-
tronic by braking.
i The last speed stored is cleared when you
switch off the engine.
Permanent SPEEDTRONIC You can use the on-board computer to limit
the speed permanently to avalue between
160 km/h (e.g. for driving on winter tyres)
and the maximum speed ( Ypage 241).
Shortly before the store dspeed is reached, it
appears in the multifunction display.
Permanent SPEEDTRONIC remains active,
even if variable SPEEDTRONIC is deactivated.
You cannot exceed the stored limit speed,
even if you depress the accelerator pedal
beyond the pressure point (kickdown). DISTRONIC PLUS
Important safety notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. It
brakes automatically in order to avoid
exceeding the set speed.
On long and steep downhill gradients, espe-
cially if the vehicle is laden or towing a trailer,
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 a slower-moving vehicle is detected in front,
DISTRONIC PLUS causes your vehicle to brake and maintain the preset distance to the
vehicle in front. G
WARNING
Do not change down for additional engine
braking on a slippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid. G
WARNING
DISTRONIC PLUS is only an aid designed to
assist driving. The driver remains fully respon-
sible for the vehicle's distance from other
vehicles, the vehicle's speed and for braking
in good time.
DISTRONIC PLUS does not react in particular
to:
R pedestrians
R stationary obstacles on the road, e.g. stop-
ped or parked vehicles
R oncoming and crossing traffic
DISTRONIC PLUS may not detect narrow vehi-
cles driving in front,e .g. motorcycles, or vehi-
cles driving on a different line. Therefore,
always pay attention to traffic conditions even
when DISTRONIC PLUS is activated. Other-
wise, you may fail to recognise dangers in
time, cause an accident and injure yourself
and others. G
WARNING
DISTRONIC PLUS cannot take account of road
and traffic conditions. If DISTRONIC doe snot
recognise or no longer recognises the 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 a lane with faster moving
traffic
R in complex driving situations or where lanes
are diverted, e.g. at roadworks on a motor-
way Driving systems
183Driving and parking
Z

Engine (4-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
Top up
coolant The coolant level is too low.
X
Top up the coolant, observing the warning notes when doing so
(Y page 324).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ?
Stop vehicle Sw.
eng. Off The coolant is too hot.
Aw
arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit a qualified specialist
workshop immediately. The poly-V-belt may have torn.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
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 a qualified specialist workshop.
If the poly-V-belt is OK:
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X Visit a qualified specialist workshop. ? The fan motor is faulty.
X
If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving on
mountain roads and stop-start traffic. 268
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
# The battery is no
tbeing charged.
Aw arning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
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 a qualified specialist workshop.
If the poly-V-belt is OK:
X Visit a qualified specialist workshop. 4
Check eng. oil
level 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 323).
X If necessary, top up the engine oil (Y page 324).
X Have the engine checked at a qualified 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. C There is only a very small amount of fuel in the fuel tank.
The auxiliary heating cannot be operated.
X
Refuel at the nearest filling station without fail. ¸
Replace
air cleaner Vehicles with a diesel engine: the engine air filter is dirty and must
be replaced.
X
Visit a qualified specialist workshop. !
Clean
the fuel fil‐
ter Vehicles with a diesel engine: there is water in the fuel filter. The
water must be drained off.
X
Visit a qualified specialist workshop. Display messages
269On-board computer and displays Z

Engine (12-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
+
Top
up coolant See
Owner's Manual The coolant level is too low.
X
Top up the coolant, observing the warning notes when doing so
(Y page 324).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ?
Coolant Stop vehi‐
cle Switch engine
off The coolant is too hot.
Aw
arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit a qualified specialist
workshop immediately. The poly-V-belt may have torn.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
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 a qualified specialist workshop.
If the poly-V-belt is OK:
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X Visit a qualified specialist workshop. ? The fan motor is faulty.
X
If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving on
mountain roads and stop-start traffic. 270
Display messagesOn-board computer and displays