engine coolant MERCEDES-BENZ C-CLASS SALOON 2007 User Guide

Troubleshooting
28
2 Problem Possible cause/consequence Suggested solutions
D
The red coolant warning
lamp lights up while the
engine is running. You will
also hear a warning tone. The coolant temperature has
exceeded 130
†. The engine is
not being cooled sufficiently and
may be damaged .
The coolant level may be too low. X
Stop the vehicle as soon as possible. Pay attention to the traffic
conditions as you do so.
X Allow the engine and coolant to cool.
X Check the coolant level. Observe the warning note s
( Y page 209). Top up the coolant if necessary.
X Have the coolant system checked at a qualified specialist work-
shop if the coolant needs topping up more often than usual .
If the coolant level is correct, the radiator fan may be faulty. In this
case:
X Do not continue driving under any circumstances .
X Consult a qualified specialist workshop. ±
The yellow engine diagnos-
tic warning lamp lights up
while the engine is run-
ning. Vehicles with a diesel engine: the
fuel tank has run dry. X
Start the engine three to four times after refuelling.
Emergency running mode is cancelled. The vehicle need not be
checked. Practical advice
204_AKB; 2; 3, en-G
B
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Troubleshooting
29
1 Problem Possible cause/consequence Suggested solutions
Vehicles with a petrol engine:
The engine is not running
smoothly and is misfiring. The engine electronics or
a
mechanical component of the
engine control unit have been
damaged. X
Only depress the accelerator pedal slightly.
X Have the cause rectified immediately at a qualified specialist work-
shop .
Otherwise, non-combusted fuel may get into the catalytic converter
and damage it. A coolant temperature of over
120 °C is displayed. The coolant
warning lamp may also be on and
a warning signal may sound
(
Y page 123). The coolant level is too low. The
coolant is too hot and the engin
e
is no longer being cooled suffi-
ciently. X
Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 209). Observe the warning notes
as you do so and top up the coolant if necessary. If the coolant level is correct, the
radiator fan may be faulty. The
coolant is too hot and the engin
e
is no longer being cooled suffi-
ciently. X
If the coolant temperature is less than 120°C, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. when driving on
mountain roads and stop/start driving . Practical advice
204_AKB; 2; 3, en-GB
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Service products and capacities
369Coolant
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 poin t
i When the vehicle is first delivered, it is
topped up with a coolant that will ensure
adequate antifreeze and corrosion protec -
tion.
! Only top up with coolant that has been
premixed with the desired quantity of anti -
freeze protection. You could otherwise
damage the engine.
There is more information about coolant
and topping it up on Mercedes-Benz Spec-
ifications for Service Products Sheet
310.1.
! 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 correct concentration, the boiling point of
the coolant will be around 130 °C.
The antifreeze/corrosion inhibitor concentra-
tion in the cooling system should:
R
be at least 50%. This will protect the coolin g
system against freezing down to around
-37 °C.
R not exceed 55% (antifreeze protection
down to -45 °C), otherwise heat will not be
effectively dissipated .
If the vehicle is losing coolant, top it up with
equal amounts of water and antifreeze/cor-
rosion inhibitor. Mercedes-Benz recom-
mends an antifreeze/corrosion inhibitor
which has been approved for Mercedes-Benz.
! The cooling system contains a lifetime
supply which must be renewed after 15
years, or after 250, 000 km at the latest.
Have the renewal confirmed in the Service
Booklet.
The warranty is only valid if you top up with
an antifreeze/corrosion inhibitor which
has been approved by Mercedes-Benz. Technical data
204_AKB; 2; 3, en-GB
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, 2007-06-26T23:11:51+02:00 - Seite 369