Page 287 of 481
286 OperationEngine compartmentHood
Opening
1Release leverWarning!
G
Do not pull the release lever while the vehi-
cle is in motion. Otherwise the hood could
be forced open by passing air flow.
This could cause the hood to come loose
and injure you and/or others.Warning!
G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature gauge indicates that the engine is
overheated, do not open the hood. Move
away from vehicle and do not open the hood
until the engine has cooled. If necessary,
call the fire department.
Warning!
G
You could be injured when the hood is open
– even when the engine is turned off.
Parts of the engine can become very hot. To
prevent burns, let the engine cool off com-
pletely before touching any components on
the vehicle. Comply with all relevant safety
precautions.Warning!
G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
The radiator fan may continue to run for
approximately 30 seconds or even restart
after the engine has been turned off. Stay
clear of fan blades.
Warning!
G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition coils, spark plug sockets, diagnostic
socket) of the ignition system
with the engine running
while starting the engine
if ignition is “on” and the engine is
turned manually
Page 289 of 481
288 OperationEngine compartmentChecking engine oil level
When checking the oil level
the vehicle must be parked on level
ground
with the engine at operating tempera-
ture, the vehicle must have been sta-
tionary for at least 5 minutes with the
engine turned off
with the engine not at operating tem-
perature yet, the vehicle must have
been stationary for at least 5 minutes
with the engine turned off1Oil dipstick
2Upper (max) mark
3Lower (min) mark
To check the engine oil level with the oil
dipstick, do the following:
Open the hood (
page 286).
Pull out oil dipstick1.
Wipe oil dipstick1 clean.
Fully insert oil dipstick1 into the
dipstick guide tube.
Pull out oil dipstick1 again after
approximately 3 seconds to obtain ac-
curate reading.
The oil level is correct when it is be-
tween the lower (min) mark3 and
upper (max) mark2 of oil dipstick1.
If necessary, add engine oil.
For adding engine oil, see “Adding engine
oil” (page 289).
For more information on engine oil, see
“Fuels, coolants, lubricants etc.”
(
page 449).
i
CLS 550 only:
The filling quantity between the upper and lower
marks on the oil dipstick is approximately
2.1 US qt. (2.0 l).
i
CLS 63 AMG only:
The filling quantity between the upper and lower
marks on the oil dipstick is approximately
1.6 US qt. (1.5 l).
Page 291 of 481
290 OperationEngine compartmentCoolant 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.
The coolant expansion tank is located on
the driver’s side of the engine compart-
ment.
1Marking bar in the expansion tank
2Cap
3Coolant expansion tank
Using a rag, turn cap2 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning the cap2 counter-
clockwise and remove it.
The coolant level is correct if the level:
for cold coolant: reaches marking
bar1 in the expansion tank3
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap2.
For more information on coolant, see the
“Technical data” section (
page 453).
Warning!
G
In order to avoid potentially 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 348 of 481
347 Practical hints
What to do if …
Problem
Possible cause/consequence
Suggested solution
D
The red coolant temperature
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 290).
Have the cooling system checked.
If the coolant temperature is below
248°F (120°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 temperature
warning lamp comes on while
driving and you hear a warning
sound.
The coolant temperature has exceeded
248°F (120°C).
Stop in a safe location as soon as pos-
sible 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 the
engine has cooled down.
Page 374 of 481
373 Practical hints
What 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.
H
Top up coolant
See Operator’s Manual
The coolant level is too low.
Add coolant (
page 290).
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 375 of 481
374 Practical hintsWhat 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
Z
Coolant
Stop, turn engine off
The coolant is too hot.
Stop the vehicle in a safe location or as soon
as it is safe to do so and immediately turn
off the engine.
Only start the engine again after the mes-
sage disappears. You could otherwise dam-
age the engine.
Apply the parking brake (
page 53).
Observe the coolant temperature indicator
in the instrument cluster (
page 26).
If the temperature rises again:
Contact an authorized Mercedes-Benz
Center immediately.
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.
Stop the vehicle in a safe location away from
other traffic. 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 376 of 481
375 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
Z
Coolant
Stop, turn engine off
The poly-V-belt could be broken.
Stop the vehicle in a safe location and immediately
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 au-
thorized Mercedes-Benz Center.
If it is intact:
Do not continue to drive the vehicle with this mes-
sage displayed. Doing so could result in serious en-
gine damage that is not covered by the
Mercedes-Benz Warranty.
Observe the coolant temperature indicator in the
instrument cluster (
page 26).
Drive immediately to the nearest authorized
Mercedes-Benz Center.
Page 377 of 481
376 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
Z
The cooling fan for the coolant is
malfunctioning.
Observe the coolant temperature indicator in the
instrument cluster (
page 26).
If the coolant temperature is under 120°C, you may
continue driving to an authorized Mercedes-Benz
Center.
Avoid placing heavy loads on the engine (e.g. by
driving uphill) as well as stop-and-go traffic.
Have the fan replaced as soon as possible.
±
Display malfunction
Visit workshop
Certain electronic systems are
unable to relay information to
the control system. The follow-
ing systems may have failed:
Coolant temperature display
Tachometer
Cruise control display
Have the electronic systems checked by an autho-
rized 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.
