engine coolant MERCEDES-BENZ SLK ROADSTER 2012 User Guide

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 Let the engine and coolant cool down.
X Check the coolant level and top up the coolant (Y page 251).
Observe the warning notes as you do so.
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 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. ?
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.
The engine is not being cooled sufficiently and may be damaged.
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 Let the engine and coolant cool down.
X Check the coolant level and top up the coolant (Y page 251).
Observe the warning notes as you do so.
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 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. 232
Warning and indicator lamps in the instrument clusterOn-board computer and displays

H
Environmental note
When topping up the 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
Centre.
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 changing the engine oil and oil filter after
missing the change interval required by
the service system
R using engine oil additives
! Do not add too much oil. Topping up with
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 :anti-clockwise and remove it.
X Top up the engine oil.
If the oil level is at or under the MIN mark
on the oil dipstick, add 0.5 to 1.0 litre of
engine oil. X
Replace cap :on the filler neck and turn
clockwise.
Make sure that the cap locks into place
securely.
X Chec kthe oil level again with the oil dip-
stick (Y page 250).
Further information on engine oil
(Y page 307). Checking and adding other service
products
Checking the coolant level G
WARNING
The cooling system is pressurised. Therefore,
only unscrew the cap once the engine has
cooled down. The coolant temperature gauge
must display less than 70 †.Otherwise, you
could be scalded if hot coolant escapes. X
Park the vehicle on a level surface.
Only check the coolant level if the vehicle
is on a level surface and the engine has
cooled down.
X Turn the key to position 2in the ignition
lock (Y page 127).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 127).
X Check the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
70 †.
X Turn the key to position 0(Ypage 127) in
the ignition lock. Engine compartment
251Maintenance and care Z

X
Slowly turn cap ;half a turn anti-clock-
wise to allow excess pressure to escape.
X Turn cap ;further anti-clockwise and
remove it.
If the coolant is at the level of marker bar
= in the fille rneck when cold, there is
enough coolant in coolant expansion
tank :.
If the coolant level is approximately
1.5 cm above marker bar =in the filler
neckw hen warm, there is enough coolant
in coolant expansion tank :.
X If necessary, top up with coolant that has
been tested and approved by Mercedes-
Benz.
X Replace cap ;and turn it clockwise as far
as it will go.
For further information on coolant, see
(Y page 308).
Topping up the windscreen washer sys-
tem/headlampc leaning systemG
WARNING
Windscreen washer fluid/antifreeze is highly
flammable. Avoid spilling windscreen washer
fluid/antifreeze on hot engine components as
it can ignite and burn. Severe burns could be
the result. X
To open: pull cap:upwards by the tab.
X Top up with the premixed washer fluid.
X To close: press cap :onto the filler neck
until it engages. The washer fluid reservoir is used for both the
windscreen washer syste mand the headlamp
cleaning system.
Further informatio nonwindscreen washer
fluid/antifreeze (Y page 309). Maintenance
ASSYST PLUS service interval display
Service messages Information on the type of service and service
intervals (see separate Service Booklet).
You can obtain further information from a
Mercedes-Benz Service Centre.
The ASSYST PLUS service interval display
informs you when the nex tservice is due.
If a service due date has been exceeded, you
also hear an acoustic signal.
The multifunction display shows a service
message for a few seconds, e.g.
Next service A due in .. days Service A due
Service A overdue by ... days
The letter indicates which service is due.
A stands for a minor service and
B for a major
service. A number or another letter may be
displayed after the letter. This figure indicates
any necessary additional maintenance work
to be performed.
If you report this displayed information to a
qualified specialist workshop, for example a
Mercedes-Benz Service Centre, they can
infor myou of the costs the service will incur.
The ASSYST PLUS service interval display
does not take into account any periods of
time during which the battery is disconnec-
ted. 252
MaintenanceMaintenance and care

numbe
r(VIN) is also stamped onto the vehicle
body.
It is located in the centre tunnel on the front-
passenger side. X
Slide the front-passenger seat to its front-
most position.
X Fold trim :upwards.
You will see vehicle identification number
(VIN) ;. Engine number
The engine number is stamped into the crank-
case. More information can be obtained from
any Mercedes-Benz Service Centre. Service products and capacities
Important safety notes
G
WARNING
When handling, storing and disposing of any
service products, please observe the relevant
regulations, as you could otherwise endanger
yourself and others.
Keep service products away from children.
To protect yourh ealth, do not allow service
products to come into contact with your eyes
or open wounds. See a doctor immediately if
any service product is swallowed. H
Environmental note
Dispose of service products in an environ-
mentally-responsible manner. Service products include the following:
R
fuels (e.g. petrol, diesel)
R lubricants (e.g. engine oil, transmission oil)
R coolant
R brake fluid
R windscreen washer fluid
R climate control system refrigerant
Components and service products must be
matched. Mercedes-Benz recommends that
you use products tested and approved by
Mercedes-Benz .They are listed in this
Mercedes-Ben zOwner's Manual in the appro-
priate section.
You can identify service products approved
by Mercedes-Ben zby the following inscrip-
tions on the container:
R MB-Freigabe (e.g. MB-Freigabe 229.51)
R MB Approval (e.g. MB Approval 229.51)
Other designations or recommendations indi-
cate a level of quality or a specification in
accordance with an MB Sheet number (e.g.
MB 229.5). The yhave no tnecessarily been
approved by Mercedes-Benz.
Further information can be obtained from any
Mercedes-Benz Service Centre or on the
Internet at http://bevo.mercedes-benz.com. Fuel
Important safety notes G
WARNING
Fuel is highly flammable. Fire, naked flames
and smoking are therefore prohibited when
handling fuels.
Switch off the engine before refuelling. G
WARNING
Avoid contact with fuels.
It is hazardous to your health if your skin
comes into direct contact with fuels or you
breathe in fuel vapours. Service products and capacities
303Technical data Z

Additives
!
Do no tuse any additives with the engine
oil. This could damage the engine.
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 regularo
il
changes using an approved engine oil with the
appropriate SA Eclassification. Brake fluid
G
WARNING
Over a period of time, the brake fluid 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.I nformation abou tapproved brake fluid
can be obtained at any qualified specialist
workshop or on the Internet at
http://bevo.mercedes-benz.com.
i Have the brake fluid regularly checked at
a qualified specialist workshop.
There is usually a notice in the engine com-
partment to remind you when the next
brake fluid change is due. 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 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 coolin gsystem is not
sufficiently protected from corrosion and
overheating.
! The engine cooling system is filled with
coolant, which mus tbe renewed after 308
Service products and capacitiesTechnical data

15 years or after 250,000 kilometres at the
latest.
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It performs the
following tasks:
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 operatio nwill be around
130 †.
The antifreeze/corrosio ninhibitor concentra-
tio nint he engine cooling system should:
R be at least 50%. This will protect the engine
cooling system against freezing down to
around -37 †.
R not exceed 55% (antifreeze protection
down to -45 †). Otherwise, heat will not be
dissipated as effectively.
If the vehicle has lost coolant, top it up with
equal amounts of water and antifreeze/cor-
rosion inhibitor. Mercedes-Ben zrecom-
mends an antifreeze/corrosion inhibitor con-
centrate in accordance with MB Specifica-
tions for Service Products 310.1.
The coolant is checked with every mainte-
nance interval at a qualified specialist work-
shop.
i When the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures
adequate antifreeze and corrosion protec-
tion. Washer fluid
G
WARNING
Windscreen washer fluid/antifreeze is highly
flammable. Avoid spilling windscreen washer
fluid/antifreeze on hot engine components as
it can ignite and burn. Severe burns could be
the result. !
Only use washer fluid that is suitable for
plastic lamp lenses, e.g. MB SummerFit or
MB WinterFit .Unsuitabl ewasher fluid
could damage the plastic lenses of the
headlamps.
! Do no tuse distilled or de-ionised water in
the washer fluid reservoir. Otherwise, the
level sensor may be damaged.
! Only the washer fluids SummerFit and
WinterFit can be mixed. Otherwise, the
spraying nozzles could become blocked.
At temperatures above freezing:
X Fill the washer fluid reservoir with a mixture
of water and washer fluid, e.g. MB Sum-
merFit.
X Mix 1 part MB SummerFit to 100 parts
water.
At temperatures below freezing:
X Fill the washer fluid reservoir with a mixture
of water and washer fluid, e.g. MB Winter-
Fit. Adapt the mixing ratio to the outside
temperatures.
X Down to Ò10 †: mix 1 part MB WinterFit to
2 parts water.
X Down to Ò20 †: mix 1 part MB WinterFit to
1 part water.
X Down to Ò29 †: mix 2 parts MB WinterFit
to 1 part water.
i Add washer fluid concentrate, e.g. MB
SummerFit or MB WinterFit, to the washer
fluid all year round. Service products and capacities
309Technical data Z