2010 MERCEDES-BENZ CLS COUPE coolant temperature

Engine
Problem Possible causes/consequences and
M Solutions
;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running.
There may be a fault, for example:
R
in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with petrol engines)
R the fuel system
The emission limit values may be exceeded and the engin emay
be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop. ;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running.
Vehicles with a diesel engine: the fuel tan
khas been run dry
(Y page 146).
X Start the engine three to four times after refuelling.
If the yellow engine diagnostics warning lamp goes out, emer-
gency running mode is cancelled. The vehicle need no tbe
checked. 8
The yellow reserve fuel
warning lamp lights up
while the engine is run-
ning.
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. ?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the
star
toft he scale. The temperature sensor for the coolant temperature gauge is
faulty.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
X
Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
X Apply the parking brake.
X Consult a qualified specialist workshop. 244
Warning and indicator lamps in the instrument clusterOn-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.
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 Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Allow the engine and coolant to cool.
X Check the coolant level and top up the coolant (Y page 268).
Observe the warning notes.
X If the coolant needs topping up more often than usual, have the
engine coolant system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in moun-
tainous terrain, and stop-start driving. ?
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 Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Allow the engine and coolant to cool.
X Check the coolant level and top up the coolant (Y page 268).
Observe the warning notes.
X If the coolant needs topping up more often than usual, have the
engine coolant system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in moun-
tainous terrain, and stop-start driving. Warning and indicator lamps in the instrument cluster
245On-board computer and displays Z

X
Slowly insert oil dipstick :into the oil dip-
stick tube to the stop ,and take it ou tagain.
The oil level is correc tifthe level is between
MIN mark =and MAX mark ;.
X Top up the oil if necessary.
Adding engine oil 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. Example: engine oil cap
X
Turn cap :anti-clockwise and remove it.
X Top up with the amount of oil required.
Fill carefully to the maximum mark on the oil
dipstick.
i Depending on the engine, the difference
between the minimum mark and the maxi-
mum mark is approximately 1.5 – 2 litres.
! Do not add too much oil. If the oil level is
above the "max" mark on the dipstick, too
much oil has been added. This can lead to
damage to the engine or the catalytic con-
verter. Have excess oil siphoned off.
Further information on engine oil
(Y page 320).
X Replace cap :on the filler neck and
tighten clockwise.
Ensure that the cap locks into place
securely. Checking and adding other service
products
Checking the coolant level Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
X
Turn the key to position 2(Y page 129) in
the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 129).
X Check the coolant temperature display in
the instrument cluster. G
Risk of injury
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
Slowly tur ncap : half a turn anti-clock-
wise and 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 ;.268
Engine compartmentMaintenance and care

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 322).
Windscreen washer system and head-
lamp cleaning system The washer fluid reservoir is used for both the
windscree nwasher system and the headlamp
cleaning system.
i Vehicle components and their service
products must match .Mercedes-Benz rec-
ommends that you use products that have
been tested and approved by Mercedes-
Benz. These are listed under the relevant
section in this Mercedes-Benz Owner's
Manual.
You can recognise service products
approved by Mercedes-Benz by the follow-
ing inscription on the containers:
R MB-Freigabe (e.g. MB-Freigabe 229.51)
R MB Approval (e.g. MB Approval 229.51)
Other designations or recommendations
that relate to a level of quality or a specifi-
cation in accordance with an MB Sheet
number (such as MB 229.5) have not nec-
essarily been approved by Mercedes-Benz.
You can obtain further information from
any Mercedes-Benz Service Centre. G
Risk of fire
Windscreen washer fluid is highly flammable.
Fire, naked flames and smoking are prohibi-
ted when handling washer fluid concentrate.
! Only use washer fluid concentrate which
is suitable for plastic lamp lenses. Unsuit-
able washer fluid concentrat ecould dam-
age the plastic lamp lenses of the head-
lamps. !
Do not use distilled or de-ionised water in
the washer fluid reservoir. Otherwise, the
level sensor may be damaged.
i Add windscreen washer concentrate, e.g.
MB SummerFit, to the washer fluid all year
round. Example: washer fluid reservoir
X
Mix the windscreen washer fluid in a con-
tainer beforehand.
X At temperatures above freezing: fill the
washer fluid reservoir with amix of water
and windscreen washer concentrate (e.g.
MB SummerFit).
X At temperatures below freezing: fill the
washer fluid reservoir with amix of water
and windscreen washer concentrate (e.g.
MB WinterFit). Adapt the mixing ratio to the
outside temperatures.
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. 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. Maintenance
269Maintenance and care Z

Brake fluid
G
Ris
kofa ccident
The brake fluid constantly absorbs moisture
from the air; this lower sits boiling point.
If the boiling point of the brake fluid is too low,
vapour pockets may for minthe brake system
when the brakes are applied hard (e.g. when
driving downhill). This would impair braking
efficiency.
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. Information about approved brake flu-
ids can be obtained from any Mercedes-Benz
Service Centre.
i There is usually a notice in the engine
compartmentt o remind you when the next
brake fluid change is due. Coolant
Important safety notes 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 i
When the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures
adequate antifreeze and corrosion protec-
tion.
! Only add coolant that has been premixed
with the desired antifreeze protection. You
could otherwise damage the engine.
Further information on coolants and on fill-
ing can be found in the Mercedes-Benz
Specifications for Servic eProducts, MB
Approval 310.1, e.g. on the Internet at
http://bevo.mercedes-benz.com .You can
also consult a Mercedes-Benz Service
Centre.
! Always use a suitable coolant mixture,
even in countries where high temperatures
prevail.
Otherwise, the cooling system will not be
sufficiently protected from corrosion, and
the boiling point will be too low.
If antifreeze/corrosion inhibitor is present in
the correc tconcentration, the boiling point of
the coolant will be around 130 †.
The antifreeze/corrosion inhibitor concentra-
tion in the engine cooling system should:
R be at least 50%. This will protec tthe 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
which has been approved for Mercedes-Benz.
! The engine cooling system is filled with
coolant that must be renewed after 15
years, or after 250,000 km at the latest. 322
Service products and capacitiesTechnical data -