2007 MERCEDES-BENZ CLK550 COUPE engine overheat

378 Practical hints
What to do if …?
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
#The battery is no longer charging.
Possible causes:

broken poly-V-belt

alternator malfunctioning
Stop immediately in a safe location or
as soon as it is safe to do so and check
the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an
inoperative water pump which may
result in damage to the engine. Notify
an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest
authorized Mercedes-Benz Center.
Low voltage
Charge batteryThe battery has insufficient voltage.Start the engine (page 50).
Low voltage
Switch off
consumersThe battery has insufficient voltage.Turn off unnecessary electrical con-
sumers.

380 Practical hints
What to do if …?
Display symbolDisplay messagePossible cause/consequencePossible solution
úVisit workshopThere may be a malfunction in the

fuel injection system

ignition system

exhaust system

fuel system
Have the measuring system checked
by an authorized Mercedes-Benz Cen-
ter.
B Top up coolant
See Operator’s ManualThe coolant level is too low.Add coolant (page 310).
If you have to add coolant frequently,
have the cooling system checked by
an authorized Mercedes-Benz Center.
Warning!G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You could be seriously burned.
!Do not ignore the low engine coolant level
warning. Extended driving with the message and
symbol displayed may cause serious engine
damage not covered by the Mercedes-Benz Lim-
ited Warranty.
Do not drive without sufficient amount of coolant
in the cooling system. The engine will overheat,
causing major engine damage.

381 Practical hints
What to do if …?
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant
Stop, turn engine offThe coolant is too hot.
Among other possible causes, the
poly-V-belt could be broken.Stop the vehicle in a safe location or
as soon as it is safe to do so.
Apply the parking brake (page 59).
Turn off the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Contact
an authorized Mercedes-Benz Center.
If it is intact:
Wait for the message to disappear be-
fore restarting the engine.
Doing otherwise could result in seri-
ous engine damage that is not covered
by the Mercedes-Benz Limited War-
ranty.
(Continued on next page)

382 Practical hints
What to do if …?
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
Observe the coolant temperature indicator in
the instrument cluster (
page 26).
If the temperature rises again:
Contact an authorized Mercedes-Benz
Center immediately.
•The cooling fan for the coolant is mal-
functioning.Observe the coolant temperature indicator in the
instrument cluster (
page 26).
Have the fan replaced as soon as possible.
Warning!G
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 open-
ing the hood. Stay away from the engine if
you see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.!The engine should not be operated with the
coolant temperature above 248°F (120°C). Do-
ing so may cause serious engine damage which
is not covered by the Mercedes-Benz Limited
Warranty.