engine overheat MERCEDES-BENZ SLK250 2012 R172 Owner's Manual

Exhaust check
G
WARNING
Inhalation of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
Do no trun the engin einconfined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work at peak efficiency if
they are serviced exactly in accordance with
the manufacturer's specifications. For this
reason, all work on the engine should only be
carried out by qualified and authorized
Mercedes-Benz technicians.
The engine settings must not be changed
under any circumstances. Furthermore, all
specific service work must be carried out at
regular intervals and in accordance with the
Mercedes-Benz service requirements. Details
can be found in the Maintenance Booklet. Brakes
Important safety notes G
WARNING
On slippery road surfaces, never downshift in
order to obtain braking action. This could
result in drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of loss of control. G
WARNING
Make sure that you do not endanger other
road users when you apply the brakes. Downhill gradients !
On long and steep gradients, you must
reduce the load on the brakes by shifting
early to a lower gear. This allows you to take
advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road
surface. This could cause damage to the
drive train. This type of damage is not
covered by the Mercedes-Benz warranty.
Heavy and light loads G
WARNING
Depressing the brake pedal constantly results
in excessive and premature wear to the brake
pads.
It may also cause the brakes to overheat,
seriously impairing their effectiveness. It may
then not be possible to stop the vehicle in
sufficient time to avoid an accident.
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
airflow to cool the brakes more quickly.
Wet roads G
WARNING
After driving in heavy rain for some time
without applying the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion. Driving tips
153Driving and parking Z

control. Your vehicle's ABS will not prevent
this type of loss of control.
Drive particularly carefully on slippery road
surfaces. Avoid sudde nacceleration, steering
and braking maneuvers. Do not use cruise
control.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X Vehicles with manual transmission:
shift to neutral.
X Vehicles with automatic transmission:
shift the transmissio nto position N.
i For more information on driving with
snow chains, see (Y page 297).G
WARNING
Make sure that you do not endanger other
road users when you apply the brakes. 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. Select shift range 1,2or 3
on vehicles with automatic transmission in
order to use the engine's braking effect,
which 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
conditions make it appropriate to maintain a
steady speed for a prolonged period. You can
store any road speed above 20 mph
(30 km/h). G
WARNING
The cruise control is a convenience system
designed to assist the driver during vehicle operation. The driver is and must always
remain responsible for the vehicle's speed
and for safe brake operation.
Only use the cruise control if the road, traffic,
and weather conditions make it advisable to
travel at a constant speed.
R
The use of the cruise control can be
dangerous on winding roads or in heavy
traffic because conditions do not allow safe
driving at a constant speed.
R The use of the cruise control can be
dangerous on slippery roads. Rapid
changes in tire traction can result in wheel
spin and loss of control.
R Deactivate the cruise control when driving
in fog.
The "Resume" function should only be
operated if the driver is fully aware of the
previously set speed and wishes to resume
this particular preset speed.
Cruise control lever 0002
To activate or increase speed
0003 To activate or reduce speed
0023 To deactivate cruise control
0022 To activate at the current speed/last
stored speed
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds. After that, it is permanently
shown in the status indicator:
R USA only: e.g., CRUISE 55Miles R
Canada only: e.g. 001090 Km/h156
Driving systemsDriving and parking

Deactivating cruise control
There are several ways to deactivate cruise
control:
X
Briefly press the cruise control lever
forwards 0023.
or
X Brake.
Cruise control is automatically deactivated if:
R you engage the electric parking brake.
R you are driving at less than 20 mph
(30 km/h)
R ESP ®
intervenes or you deactivate ESP ®
.
R you shift into neutral in a vehicle with
manual transmissio nwhile driving or
depress the clutch pedal for longer than six
seconds.
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 CruiseControl Off message in the multifunction
display for approximately five seconds.
i When you switch off the engine, the last
speed stored is cleared. DISTRONIC PLUS
Important safety notes i
DISTRONIC PLUS is not available on AMG
vehicles.
DISTRONIC PLUS regulates the speed and
automatically helps you maintain the
distance to the vehicle detected in front.
DISTRONIC PLUS brakes automatically so
that the set speed is not exceeded.
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, which relieves the load
on the brake system and prevents the brakes
from overheating and wearing too quickly.
If DISTRONIC PLUS detects a slower-moving
vehicle in front, your vehicle is braked in order
to maintain the preset distance to the vehicle
in front.
G
WARNING
The DISTRONIC PLUS requires familiarity with
its operational characteristics. We strongly
recommend that you review the following
information carefully before operating the
system. G
WARNING
The DISTRONIC PLUS is a convenience
system. Its speed adjustment reduction
capability is intended to make cruise control
more effective and usable when traffic speeds
vary. It is not however, intended to, nor does
it, replace the need for extreme care.
The responsibility for the vehicle's speed,
distance to the preceding vehicle and, most
importantly, brake operation to ensure a safe
stopping distance, always remains with the
driver.
The DISTRONIC PLUS cannot take street and
traffic conditions into account.
Complex driving situations are not always
fully recognized by the DISTRONIC PLUS. This
could result in wrong or missing distance
warnings.
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
(Y page 194) and operational.
If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control in the speed range between 20 mph
(Canada: 30 km/h) and 120 mph (Canada:
200 km/h). If a vehicle is driving in front of
you, it operates in the speed range between
0 mph (0 km/h) and 120 mph (Canada:
200 km/h).
Do not use DISTRONIC PLUS while driving on
roads with steep gradients. 158
Driving systemsDriving and parking

Coolant temperature display
G
WARNING
Driving when your engine is overheated can
cause some fluids which may have leaked into
the engine compartment to catch fire. You
could be seriously burned.
Steam from an overheated engine can cause
serious burns which can occur jus tby opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of the
vehicle and do no tstand nea rthe vehicle until
the engine has cooled down.
The coolant temperature gauge is in the
instrumentc luster on the right-hand side.
Under normal operating conditions and with
the specified coolan tlevel, the coolant
temperature may rise to 248 ‡ (120 †).
! Adisplay message is shown if the coolant
temperature is too high.
If the coolant temperature is over
248 ‡(120 †), do not continue driving. The
engine will otherwise be damaged. Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached. Outside temperature display
The outside temperature display is in the
multifunction display (Y page 183).G
WARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose. Indicated temperatures just above the
freezing point do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
Changes in the outside temperature are
displayed after a shor tdelay. Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
Cruise control (Y page 156) activated:
The segments light up from the stored speed
to the maximum speed.
DISTRONIC PLUS (Y page 158) activated:
One or two segments in the set speed range
light up.
DISTRONIC PLUS detects a vehicle in front:
The segments between the speed of the
vehicle in fron tand the stored speed light up. Operating the on-board computer
Overview The on-board compute
ris activated as soon
as you turn the SmartKey to position 1in the
ignition lock.
You can control the multifunction display and
the settings in the on-board computer using
the buttons on the multifunction steering
wheel. Displays and operation
181On-board computer and displays Z

Display messages Possible causes/consequences and
0001 Solutions
000C The engine fan is defective.
X
At coolant temperatures under 248 ‡(120 †), drive to th enext
qualified specialist workshop.
X Avoid subjecting the engin eto heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. 000C
Coolant Stop car,
switch engine off The coolant is too hot.
X
Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X Wait until the display message disappears before restarting the
engine. Otherwise, the engine could be damaged.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit a qualified specialist
workshop immediately. G
WARNING
Driving when your engine is overheated can cause some fluids which may have leaked into the
engine compartment to catch fire. You could be seriously burned.
Steam from an overheated engine can cause serious burns which can occur just by opening the
engine hood. Stay away from the engine if you see or hear steam coming from it.
Stop the vehicle in a safe location away from other traffic. Turn off the engine, get out of the
vehicle and do not stand near the vehicle until the engine has cooled down.
! If the coolant temperature is over 248 ‡(120 †), do not continue driving. The engine will
otherwise be damaged. Display messages
217On-board computer and displays Z

Display messages Possible causes/consequences and
0001 Solutions
000A The battery is no
tbeing charged.
Possible causes are:
R a defective alternator
R a torn poly-V-belt
R a malfunction in the electronics
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Open the hood.
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 not damaged:
X Visit a qualified specialist workshop. 0012
Check Engine Oil
At Next Refueling The engine oil level has dropped to the minimum level.
Aw
arning tone also sounds.
X Chec kthe oil level when next refueling, at the latest
(Y page 261).
X If necessary, add engine oil (Y page 262).
X Have the engine checked at a qualified specialist workshop if
engine oil needs to be added more often than usual. Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
! The oil level is too low. Avoid long journeys with too little engine oil. There is a risk of
engine damage.
The display messages and the corresponding symbol that indicate that the oil level is too
low must not be ignored. 218
Display messagesOn-board computer and displays

G
WARNING
Driving when youre ngine is overheated can cause som efluids which may have leaked into the
engine compartmen tto catch fire. You could be seriously burned.
Steam from an overheated engine can cause serious burns which can occur just by opening the
engine hood. Stay away from the engine if you see or hear steam coming from it.
Stop the vehicle in a safe location away from other traffic. Turn off the engine, get out of the
vehicle and do not stand near the vehicle until the engine has cooled down.
! If the coolant temperature is over 248 ‡(120 †), do not continue driving. The engine will
otherwise be damaged. Driving systems
Problem Possible causes/consequences and
0001 Solutions
000C
The red distance
warning lamp lights up
while the vehicle is in
motion. A warning tone
also sounds.
G
Risk of accident
You are approaching a vehicle or a stationary obstacle in you rline
of travel at too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
More information about DISTRONIC PLUS (Y page 158) and
PRE-SAFE ®
Brake (Y page 62). Warning and indicator lamps in the instrument cluster
237On-board computer and displays Z

Adding engine oil
G
WARNING
If engine oil comes into contact with hot
engine parts, it may ignite and you could burn
yourself .Do not spill any engine oil on hot
engine parts. H
Environmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
! Only use engine oils and oil filters that
have been approved for vehicles with a
service system. You can obtain a list of the
engine oils and oil filters tested and
approved in accordance with the
Mercedes-Benz Specifications for Service
Products at any Mercedes-Benz Service
center.
Damage to the engine or exhaust system is
caused by the following:
R using engine oils and oil filters that have
not been specifically approved for the
service system
R replacing engine oil and oil filters after
the interval for replacement specified by
the service system has been exceeded
R using engine oil additives.
! Do not add too much oil. adding too much
engine oil can result in damage to the
engine or to the catalytic converter. Have
excess engine oil siphoned off. Example: engine oil cap
X
Turn cap 0002counterclockwise and remove
it.
X Add engine oil.
If the oil level is at or below the MIN mark
on the oil dipstick, add 0.55 US qt to
1.1 US qt (0.5 to 1.0 l)of engine oil.
X Replace cap 0002on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level again with the oil
dipstick (Y page 261).
Further information on engine oil
(Y page 326). Checking and adding other service
products
Checking the coolant level G
WARNING
In order to avoid any potentially serious burns:
R use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system, or
if the coolant temperature display indicates
that the coolant is overheated.
R do not remove the pressure cap on the
coolant reservoir if the coolant temperature
is above 158 ‡(70 †). Allow the engine to
cool dow nbefore removing the cap. The
coolant reservoir contains hot fluid and is
under pressure. 262
Engine compartmentMaintenance and care

Fuel
Important safety notes G
WARNING
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious
personal injury.
Never allow sparks, flames or smoking
materials near gasoline.
Turn off the engine before refueling.
Wheneve ryou are around gasoline, avoid
inhaling fumes and any skin or clothing
contact.
Direct skin contact with fuels and the
inhalation of fuel vapors are damaging to your
health.
Tank capacity Total capacity
18.5 US gal (70.0 l)
Of which reserve
Approx. 2.4 US gal
(9.0 l) Gasoline
Fuel grade
!
Do not use diesel to refuel vehicles with a
gasoline engine. Even small amounts of the
wrong fuel result in damage to the fuel
system and engine.
! You should only refuel with unleaded
premium-grade gasoline as this avoids
damaging the catalytic converter.
If engine running problems are apparent,
have the cause checked immediately and
repaired. Excess unburned fuel can
otherwise enter the catalytic converter,
leading to overheating and possibly
causing a fire.
! To ensure the longevity and full
performance of the engine, only premium-
grade unleaded gasoline may be used. If there is no premium-grade unleaded
gasoline available and regular unleaded
gasoline must be used, please observe the
following precautions:
R
only fill the fuel tank to half full with
regular 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.
R if the vehicle is carrying a light load, e.g.
two passengers without luggage, do not
allow the engine to rev above 3000 rpm.
R if the vehicle is fully loaded or is being
operated in mountainous terrain, do not
depress the accelerator pedal further
than 0001of the pedal travel.
Only refuel with premium-grade unleaded
gasoline with a minimum octane number of
91.
Reformulated Gasoline (RFG) and/or
unleaded gasoline with additives can be used.
However, the concentration of additives in
the fuel must be less than 10%, e.g.
R Ethanol
R TAME
R ETBE
R IPA
R TBA
For MTBE, the concentration should not
exceed 15%.
The concentration of methanol in gasoline
including other additives must not exceed
3%.
Using mixtures of methanol and ethanol is not
permitted. Gasohol, a mixture of 10% ethanol
and 90% unleaded gasoline, can be used.
All of these mix fuels must fulfill the fuel
requirements, e.g.:
R knock resistance
R boiling point
R vapor pressure Service products and filling capacities
325Technical data Z

!
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.
The coolant is a mixture of water and
antifreeze/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
coolant under operating conditions is
approximately 266 ‡ (130 †).
The antifreeze/corrosion inhibitor
concentration 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.
If the vehicle has lost coolant, add equal
amounts of water and antifreeze/corrosion
inhibitor. Mercedes-Benz recommends an
antifreeze/corrosion inhibitor concentrate in
accordance with MB Specifications for
Service Products 310.1.
The coolant is checked with every
maintenance interval at a qualified specialist
workshop.
i When the vehicle is first delivered, it is
filled with a coolant mixture that ensures
adequate antifreeze and corrosion
protection. Capacity Model Capacity
SLK 250
Approx. 10.1 US qt
(9.6 l) SLK 350
Approx. 11.0 US qt
(10.4 l) SLK 55 AMG
Approx. 10.0 US qt
(9.5 l) i
Use MB 325.0 or MB 326.0 corrosion
inhibitor/antifreeze. Washer fluid
G
WARNING
Washer solvent/antifreeze is highly
flammable. Do not spill washer solvent/
antifreeze on hot engine parts, because it may
ignite and burn. You could be seriously
burned.
! Only use washer fluid that is suitable for
plastic lamp lenses, e.g. MB SummerFit or
MB WinterFit. Unsuitable washer fluid
could damage the plastic lenses of the
headlamps.
! Do not add distilled or de-ionized water to
the washer fluid container. Otherwise, the
level sensor may be damaged.
! Only MB SummerFit and MB WinterFit
washer fluid should be mixed together. The
spray nozzles may otherwise become
blocked.
At temperatures above freezing:
X Fill the washer fluid reservoir with a mixture
of water and windshield washer fluid, e.g.
MB SummerFit.
X Add 1 part MB SummerFit to 100 parts
water. 328
Service products and filling capacitiesTechnical data