overheating MERCEDES-BENZ SLK ROADSTER 2014 Owners Manual

accelerator. The vehicle can coast with-
out use of the brakes.
- the bar empties: frequent braking
i An economical driving style involves driv-
ing at a moderate engine speed.
To achieve a higher value in the categories
Acceleration
Acceleration andConstant Constant:
R observe the gearshift recommendation
R drive the vehicle in drive program E(vehi-
cles with automatic transmission)
i On long journeys at a constant speed, e.g.
on the motorway, only the bar for Constant
Constant
will change.
i The ECO display summarises the driving
characteristics from the start of the journey to its completion. Therefore, there are
dynamic changes in the bars at the start of
a journey. During a prolonged driving time, these changes are smaller. For more
dynamic changes, perform a manual reset.
Further information on the ECO display
(Y page 204). Braking
Important safety notes G
WARNING
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.
This increases the risk of skidding and having
an accident.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients Change into a lower gear in good time on long
and steep downhill gradients. Take particular note of this when driving a laden vehicle.
i This also applies if you have activated
cruise control, SPEEDTRONIC or DIS-
TRONIC. This will use the braking effect of the engine,
so less braking will be required to maintain
vehicle speed. This relieves the load on the
brake system and prevents the brakes from
overheating and 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 distance and could
even cause the braking system to fail. There is
a risk of an accident.
Never use the brake pedal as a footrest. Do
not simultaneously depress both the brake
pedal and the accelerator pedal while driving.
! 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, 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 surfaces 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 firsttime. This may also occur after a car wash or
after driving through deep water.
You will have to depress the brake pedal more firmly. Maintain a greater distance to the vehi-
cle 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. 166
Driving tipsDriving and parking

in 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.
Use cruise control only if road and traffic con- ditions make it appropriate to maintain a
steady speed for a prolonged period. You canstore any road speed above 30 km/h.
Important safety notes If you fail to adapt your driving style, cruise
control can neither reduce the risk of acci-
dent nor override the laws of physics. Cruise
control cannot take road, weather and traffic
conditions into account. Cruise control is only an aid. You are responsible for the distance to
the vehicle in front, for vehicle speed, for
braking in good time and for maintaining lane.
Do not use cruise control:
R in road and traffic conditions which do not
allow you to maintain a constant speed, e.g. heavy traffic or winding roads.
R on slippery roads. Braking or accelerating
may cause the drive wheels to lose traction
and the vehicle could then skid.
R when there is poor visibility, e.g. due to fog,
heavy rain or snow.
If there is a change of drivers, advise the new driver of the stored speed. Cruise control lever Cruise control lever
:
To store the current speed or a higher
speed
; LIM indicator lamp
= To store the current speed and 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 cruise control
You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.
LIM indicator lamp ;on the cruise control
lever indicates which system you have selec- ted:
R LIM indicator lamp ; ;off: cruise control
is selected.
R LIM indicator lamp ;
;on: variable
SPEEDTRONIC is selected.
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds. The speed is then perma-
nently displayed in the status indicator
together with the ¯symbol.
Selecting cruise control X
Check whether LIM indicator lamp ;is off.
If it is off, cruise control is already selected. Driving systems
169Driving and parking Z

Deactivating cruise control
Cruise control lever
There are several ways to deactivate cruise
control:
X Briefly press the cruise control lever for-
wards =.
or
X Brake.
or
X Briefly press the cruise control lever in the
direction of arrow ;.
Variable SPEEDTRONIC is selected. LIM
indicator lamp :in the cruise control lever
lights up.
Cruise control is automatically deactivated if:
R you apply the electric parking brake
R you are driving at less than 30 km/h
R ESP ®
intervenes or you deactivate ESP ®
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 you shift the transmission to position N
while driving
If cruise control is deactivated, you will hear a warning tone. You will see the Cruise con‐
Cruise con‐
trol off trol off message in the multifunction dis-
play for approximately five seconds.
i The last speed stored is cleared when you
switch off the engine. DISTRONIC PLUS
General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. DIS-
TRONIC PLUS brakes automatically so that
the set speed is not exceeded.
On long and steep downhill gradients, espe-
cially if the vehicle is laden, you must select a lower gear in 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 a slower-moving vehicle is detected in front, DISTRONIC PLUS brakes your vehicle. It
maintains the preset distance to the vehicle infront.
If DISTRONIC PLUS detects that there is a risk
of a collision, you will be warned visually and acoustically. Without your intervention, DIS-
TRONIC PLUS cannot prevent a collision. An
intermittent warning tone will then sound and
the distance warning lamp will light up in the instrument cluster. Brake immediately to
increase the distance to the vehicle driving in
front, or take evasive action, provided it is
safe to do so.
For DISTRONIC PLUS to assist you, the radar
sensor system must be operational.
If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control in the speed range between 30 km/h and 200 km/h. If a vehicle is driving in front ofyou, it operates in the speed range between
0 km/h and 200 km/h.
Do not use DISTRONIC PLUS while driving on roads with steep gradients. Driving syste
ms
171Driving an d parking Z

DISTRONIC PLUS has not detected the vehi-
cle cutting in yet. The distance to this vehicle will be too short.
Narrow vehicles DISTRONIC PLUS has not yet detected the
vehicle in front on the edge of the carriage-
way, because of its narrow width. The dis-
tance to the vehicle in front will be too short.
Obstructions and stationary vehicles DISTRONIC PLUS does not brake for obsta-
cles or stationary vehicles. If, for example, the
detected vehicle turns a corner and reveals
an obstacle or stationary vehicle, DISTRONIC PLUS will not brake for these. Crossing vehicles DISTRONIC PLUS may mistakenly detect
vehicles that are crossing your lane. Activat-
ing DISTRONIC PLUS at traffic lights with
crossing traffic, for example, could cause
your vehicle to pull away unintentionally. SPEEDTRONIC
General 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, you must select a lower gear in 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.
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 182)
i The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Important safety notes If you fail to adapt your driving style, SPEED-
TRONIC can neither reduce the risk of acci-180
Driving systemsDriving an
d parking

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). Important safety notes
G
WARNING
Operating the integrated information systems and communications equipment in the vehicle
while driving will distract you from traffic con-
ditions. You could then lose control of the
vehicle. There is a risk of an accident.
Only operate these devices if road traffic con-
ditions permit. If you are unsure about the
surrounding conditions, pull over to a safe
location and make entries only while the vehi-
cle is stationary.
You must observe the legal requirements for
the country in which you are currently driving when operating the on-board computer. G
WARNING
If the instrument cluster has failed or mal-
functioned, you may not recognise function
restrictions relevant to safety. The operating
safety of your vehicle may be impaired. There is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-
ately.
The on-board computer only shows messages
or warnings from certain systems in the mul- tifunction display. You should therefore make
sure your vehicle is operating safely at all times. Otherwise, a vehicle that is not oper-
ating safely may cause an accident.
If the operating safety of your vehicle is
impaired, park the vehicle safely as soon as
possible. Consult a qualified specialist work-
shop.
For an overview, see the instrument panel
illustration (Y
page 30). Displays and operation
Instrument cluster lighting
The lighting in the instrument cluster, in the
displays and the controls in the vehicle inte-
rior can be adjusted using the brightness con-
trol knob.
The brightness control knob is on the bottom left of the instrument cluster (Y page 30).
X Turn the brightness control knob anti-
clockwise or clockwise.
If the light switch is set to Ã,Tor
L, the brightness is dependant upon
the brightness of the ambient light.
i The light sensor in the instrument cluster
automatically controls the brightness of
the multifunction display.
In daylight, the displays in the instrument
cluster are not lit. Coolant temperature gauge
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. 200
Displays and operationOn-board computer and 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 while driving
and block your view. There is a risk of an acci- dent.
Never unlock the bonnet while driving. 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.
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 85 mm. The active bonnet is triggered by pyrotechnics.
For the drive to the workshop, reset the trig-
gered active bonnet yourself. If the active
bonnet has been triggered, pedestrian pro-
tection may be limited.
Resetting G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system. 280
Engine compartmentMaintenance and care

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 342).
The brake fluid change intervals 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.co m.
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.
Comply with the important safety precautions for service products when handling coolant
(Y page 342).
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It is responsible
for the following:
R anti-corrosion protection
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 will be approx-
imately 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 -37 †.
R not exceed 55% (antifreeze protection
down to -45 †).Heat will otherwise not be
dissipated as effectively.
If the vehicle has lost coolant, top it up with
equal amounts of water and antifreeze/
corrosion inhibitor.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in accord-
ance with MB Specifications for Service Prod-
ucts 310.1. 348
Service products and capacitiesTechnical data