Page 298 of 498
297 Operation
Engine compartment
CLS 500, CLS 55 AMG1Filler cap
Unscrew filler cap1 from filler neck.
Add engine oil as required. Be careful 
not to overfill with oil.
Be careful not to spill any oil when adding. 
Avoid environmental damage caused by oil 
entering the ground or water.
Screw filler cap1 back on filler neck.
For more information on engine oil, see the 
“Technical data” section (
page 461) and 
(
page 464).
Transmission fluid level
The transmission fluid level does not need 
to be checked. If you notice transmission 
fluid loss or gear shifting malfunctions, 
have an authorized Mercedes-Benz Center 
check the transmission.Coolant level
The engine coolant is a mixture of water 
and anticorrosion/antifreeze. To check 
the coolant level, the vehicle must be 
parked on level ground and the engine 
must be cool.
!Excess oil must be siphoned or drained 
off. It could cause damage to the 
engine and catalytic converter not 
covered by the Mercedes-Benz Limited 
Warranty. 
     
        
        Page 299 of 498

298 OperationEngine compartment
The coolant expansion tank is located on 
the driver’s side of the engine compart-
ment.Coolant expansion tank
Using a rag, turn the cap slowly approx-
imately one half turn counterclockwise 
to release any excess pressure.
Continue turning the cap counterclock-
wise and remove it.
The coolant level is correct if the level 
for cold coolant: reaches the top of 
the mark (plastic bridge) visible 
through the filling opening
for warm coolant: is approximately 
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap.
For more information on coolant, see the 
“Technical data” section (
page 466).
Warning!
G
In order to avoid any possibly serious burns:
Use extreme caution when opening the 
hood if there are any signs of steam or 
coolant leaking from the cooling system, 
or if the coolant temperature gauge indi-
cates that the coolant is overheated.
Do not remove pressure cap on coolant 
reservoir if coolant temperature is 
above 158°F (70°C). Allow engine to 
cool down before removing cap. The 
coolant reservoir contains hot fluid and 
is under pressure.
Using a rag, slowly open the cap approx-
imately 
1/2 turn to relieve excess pres-
sure. If opened immediately, scalding 
hot fluid and steam will be blown out 
under pressure.
Do not spill antifreeze on hot engine 
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts. 
     
        
        Page 358 of 498

357 Practical hints
What to do if …
Problem
Possible cause/consequence
Suggested solution
D
The red coolant warning lamp 
comes on when the engine is 
running.
There is insufficient coolant in the reservoir.
If this warning lamp comes on frequently, 
there is a leak in the cooling system.
If the coolant level is correct, the electric 
radiator fan may be broken.
Immediately add coolant to prevent 
engine from overheating 
(page 297).
Have the cooling system checked.
If the coolant temperature is below 
266°F (130°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.
D
The red coolant warning lamp 
comes on while driving and you 
hear a warning sound.
The coolant temperature has exceeded 
266°F (130°C).
Stop as soon as possible and allow 
the engine and coolant to cool down.
l
The red distance warning lamp 
comes on while driving.
You are too close to the vehicle in front of you 
to maintain selected speed.
Apply the brakes immediately to in-
crease the following distance.
Warning!
G
Driving when your engine is badly overheat-
ed 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 and can occur just by opening 
the engine 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 379 of 498

378 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
(USA only)ú(Canada only)±
Visit workshop
There 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 
Center.
B 
Coolant
Check level
The coolant level is too low.
Add coolant (
page 297).
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 can 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 Limited 
Warranty.
Do not drive without sufficient amount 
of coolant in the cooling system. The 
engine will overheat causing major 
engine damage. 
     
        
        Page 380 of 498

379 Practical hints
What to do if …
During severe operation conditions and 
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbol
Display messages
Possible cause/consequence
Possible solution
Ï 
Coolant
Stop, engine off
The coolant is too hot.
Stop the vehicle in a safe location.
Only start the engine again after the 
message disappears. You could other-
wise damage the engine.
Warning!
G
Driving when your engine is badly overheat-
ed 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 and can occur just by opening 
the engine 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). Doing so may cause serious 
damage which is not covered by the 
Mercedes-Benz Limited Warranty. 
     
        
        Page 381 of 498

380 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
Ï 
Coolant
Stop, engine off
The poly-V-belt could be broken.
Stop the vehicle in a safe location and immedi-
ately 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 inoperative water pump 
which may result in damage to the engine. Notify 
an authorized Mercedes-Benz Center.
If it is intact:
Do not continue to drive the vehicle with this 
message displayed. Doing so could result in seri-
ous engine damage that is not covered by the 
Mercedes-Benz Warranty.
Observe the coolant temperature indicator in the 
instrument cluster (
page 24).
Drive immediately to the nearest authorized 
Mercedes-Benz Center.
Coolant
Visit workshop
The cooling fan for the coolant is 
malfunctioning.
Observe the coolant temperature indicator in the 
instrument cluster (
page 24).
Have the fan replaced as soon as possible. 
     
        
        Page 382 of 498
381 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
G
Display malfunction
Visit workshop 
The displays for several systems have 
malfunctioned. Some systems them-
selves may also have malfunctioned.
Continue driving with added caution.
When the multifunction display is mal-
functioning, warnings and malfunc-
tion messages might not be 
displayed.
Have the electronic systems checked 
by an authorized Mercedes-Benz 
Center.
± 
Display malfunction
Visit workshop
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 
Center.
Engine
Service
There may be a malfunction in:
the fuel injection system
the ignition system
the exhaust system
Have the engine checked as soon as 
possible by an authorized 
Mercedes-Benz Center. 
     
        
        Page 444 of 498
443 Technical data
Parts service
Warranty coverage
Identification labels
Layout of poly-V-belt drive
Engine
Rims and tires
Electrical system
Main dimensions
Weights
Fuels, coolants, lubricants etc.