Page 372 of 505

371 Practical hints
What to do if …?
ProblemPossible cause/consequenceSuggested solution
•The red coolant warning lamp
comes on when the engine is
running.There is insufficient coolant in the reservoir.Add coolant to prevent engine from
overheating (
page 320).
If this warning lamp comes on frequently,
there is a leak in the cooling system.Have the cooling system checked.
If the coolant level is correct, the electric ra-
diator fan may be broken.If the coolant temperature is below
257 °F (125 °C), you can continue
driving to the nearest authorized
Mercedes-Benz Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.
•The red coolant warning lamp
comes on while driving and you
hear a warning sound.The coolant temperature has exceeded
257 °F (125 °C).Stop as soon as possible and allow
the engine and coolant to cool down.
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.
Page 391 of 505

390 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 320).
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.
Page 392 of 505
391 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 58).
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)
Page 393 of 505

392 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.
Page 394 of 505
393 Practical hints
What to do if …?
Display symbolDisplay messagePossible cause/consequencePossible solution
4Gas cap is openA loss of pressure has been detected in
the fuel system. The fuel cap may not be
closed properly or the fuel system may be
leaky.Check the fuel cap (page 312).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an
authorized Mercedes-Benz Center.
± Certain electronic systems are unable to
relay information to the control system.
The following systems may have failed:
Coolant temperature display
Tachometer
Cruise control display
Have the electronic systems checked
by an authorized Mercedes-Benz Cen-
ter.
Page 460 of 505
459 Technical data
Parts service
Warranty coverage
Identification labels
Layout of poly-V-belt drive
Engine
Rims and tires
Electrical system
Main dimensions and weights
Fuels, coolants, lubricants, etc.
Page 465 of 505
464 Technical data
Layout of poly-V-belt drive
CLK 350 / CLK 550
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)CLK 63 AMG
1Idler pulley
2Idler pulley
3Idler pulley
4Automatic belt tensioner
5Power steering pump
6Air conditioning compressor
7Crankshaft
8Coolant pump
9Generator (alternator)
Page 473 of 505

472 Technical data
Fuels, coolants, lubricants, etc.
Capacities
Vehicle components and their respective
lubricants must match. Therefore only use
products tested and approved by
Mercedes-Benz.
Please refer to the Factory Approved Ser-
vice Products pamphlet, or inquire at your
Mercedes-Benz Center.
Warning!G
Comply with all valid regulations with
respect to handling, storing, and disposing
of service fluids. Otherwise you could
endanger persons or the environment.
Keep service fluids out of the reach of
children.
For health reasons, you should prevent
service fluids from coming into direct
contact with your eyes or any open wounds.
If a service fluid is swallowed, contact a
physician immediately.
ModelCapacityFuels, coolants, lubricants, etc.
Engine with oil filterCLK 350
CLK 550
CLK 63 AMG8.5 US qt (8.0 l)
9.0 US qt (8.5 l)
9.0 US qt (8.8 l)Approved engine oils
Automatic transmissionCLK 350
CLK 550
CLK 63 AMG9.0 US qt (8.5 l)
9.5 US qt (9.0 l)
9.3 US qt (8.5 l)MB Automatic Transmission Fluid
Rear axleCLK 350
CLK 550
CLK 63 AMG1.16 US qt (1.1 l)
1.27 US qt (1.2 l)
1.27 US qt (1.2 l)Hypoid gear oil SAE 85 W 90
Fuchs Titan EG 5010D