Page 231 of 376

231 Operation
Engine compartment
1Coolant expansion tank
Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.
Continue turning the cap to the left and 
remove it.
The coolant level is correct if the level 
for cold coolant: is up to the upper 
mark on the bracing rib of the coolant 
expansion tank (translucent)
for warm coolant: is approx. 0.6 in 
(1.5 cm) higher
Add coolant as required.
Replace and tighten cap. 
More information on coolant can be found 
in the “Technical data” section 
(
page 345).
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 engine temperature is above 
194°F (90°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 un-
der 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 254 of 376

254 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
D
The red coolant warning lamp 
lights up when the engine is run-
ning.
There is insufficient coolant in the reservoir.
If this warning lamp lights up frequently, 
there is a leak in the cooling system.
If the coolant level is correct, the electric ra-
diator fan may be broken. 
Immediately add coolant to prevent 
engine from overheating 
(page 230).
Have the cooling system checked.
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.
D
The red coolant warning lamp 
lights up 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 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 it 
cools down. 
     
        
        Page 287 of 376
287 Practical hints
What to do if …
Left display
Right display
Possible cause
Possible solution
K
Visit workshop!
The retractable hardtop is mal-
functioning.
Have the retractable hardtop checked by an au-
thorized Mercedes-Benz Center.
Lock
hardtop
The roof is not properly locked.
Push or pull on the retractable hardtop switch 
until the indicator lamp in the switch goes out 
and the roof is completely open or closed 
(page 159).
±
Display defective
Visit workshop!
Certain electronic systems are un-
able to relay information to the 
control system. The following sys-
tems may have failed:
Coolant temperature gauge
Tachometer
Cruise control display
Have the electronic systems checked by an au-
thorized Mercedes-Benz Center (
page 256).
W
Washer fluid
Check level!
The fluid level has dropped to 
about 1/3 of total reservoir ca-
pacity.
Add washer fluid (
page 233). 
     
        
        Page 347 of 376

347 Technical data
Fuels, coolants, lubricants, etc.
Windshield and headlamp washer system
Both the windshield and headlamp washer 
systems are supplied from the windshield 
washer fluid reservoir.
The windshield and headlamp washer fluid 
reservoir has a capacity of approx. 
7.4 US qt. (7 l).
Refill the reservoir with MB Windshield 
Washer Concentrate and water (or con-
centrate and commercially available 
premixed windshield washer 
solvent / antifreeze, depending on am-
bient temperatures).Windshield and headlamp washer fluid 
mixing ratio
For temperatures above freezing use 
MB Windshield Washer Concentrate “S” 
and water:
1 part “S” to 100 parts water
(40 ml “S” to 4 l water)
For temperatures below freezing use 
MB Windshield Washer Concentrate “S” 
and commercially available premixed 
windshield washer solvent / antifreeze:
1 part “S” to 100 parts solvent
(40 ml “S” to 4 l solvent).
Warning!
G
Washer solvent/antifreeze is highly flamma-
ble. Do not spill washer solvent/antifreeze 
on hot engine parts because it may ignite. 
You could be seriously burned.