engine overheat MERCEDES-BENZ S550 4MATIC 2008 W221 Owner's Manual

417 Controls in detail
Instrument cluster
Instrument cluster
A full view illustration of the instrument
cluster can be found in the “At a glance”
section of this manual (
page 28).
The instrument cluster is activated when
you:

open a door

switch on the ignition (page 344)

switch on the exterior lamps
The language setting for the multifunction
display can be changed via COMAND
(
page 238).Adjusting instrument cluster display
illumination
1Knob
Brightening illumination: Turn
knob1 clockwise.
Dimming illumination: Turn knob1
counterclockwise.
Coolant temperature gauge
The coolant temperature gauge is on the
left side in the instrument cluster
(
page 28).
Warning!G
No messages will be displayed if either the
instrument cluster or the multifunction dis-
play is inoperative.
As a result, you will not be able to see infor-
mation about your driving conditions, such
as speed or outside temperature, warning/
indicator lamps, malfunction/warning mes-
sages or the failure of any systems. Driving
characteristics may be impaired.
If you must continue to drive, please do so
with added caution. Contact an authorized
Mercedes-Benz Center as soon as possible.
iThe instrument cluster illumination is
dimmed or brightened automatically to suit am-
bient light conditions.
The instrument cluster illumination will also be
adjusted automatically when you switch on the
vehicle’s exterior lamps.
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 and can occur just
by opening the hood. Stay away from
the engine if you see or hear steam com-
ing from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out


528 Operation
Driving instructions
Brakes
To help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.Refer to the description of the Brake Assist
System (BAS or BAS Plus*) (
page 68).
Brake pad wear or a leak in the system may
be the reason for low brake fluid level in
the reservoir.
The brake fluid level in the reservoir may
be too low if the red brake warning lamp in
the instrument cluster comes on while the
engine is running and an acoustic warning
sounds (
page 601). Observe additional
messages in the multifunction display that
may appear (
page 612).
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Center.
Warning!G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking
effect. Maintain a safe distance from
vehicles in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an
accident.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO start/stop button* in position0
or1) when

the electronic parking brake is being tested
on a brake test dynamometer

the vehicle is being towed with the
front/rear axle raised
Active braking action through the ESP
® may oth-
erwise seriously damage the brake system.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.

529 Operation
Driving instructions
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Center.
Only install brake pads and brake fluid
recommended by Mercedes-Benz.After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream can cool down
the brakes faster.
High-performance brake system
(S 63 AMG and S 65 AMG only)
The high-performance brake system is de-
signed to operate under the extremely high
operating demands required to accommo-
date the performance capabilities of the
vehicle. The brakes may produce a squeak-
ing-type noise depending on the

vehicle speed

brake force applied

ambient conditions, e.g. temperature
and humidity
As with any brake system, the wear of indi-
vidual brake system components such as
brake pads or disks strongly depends on
your driving style and the conditions under which you operate the vehicle. Thus, a driv-
ing style calling for high demand braking
will cause your vehicle’s brakes to wear
more quickly.
Warning!G
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that
safe braking is substantially impaired. This
could result in an accident.
!When driving down long and steep grades,
relieve the load on the brakes by shifting into a
lower gear to use the engine’s braking power.
This helps prevent overheating of the brakes and
reduces brake pad wear.
When using the engine’s braking power, a drive
wheel may not spin for an extended period of
time, e.g. on slippery road surfaces.
This may cause serious damage to the drivetrain
which is not covered by the Mercedes-Benz Lim-
ited Warranty.
Warning!G
New vehicle brake pads and discs, and
replacement brake pads and discs may take
several hundred miles of driving until they
provide optimum braking efficiency. Until
that time, you may need to use increased
brake pedal pressure while braking. Please
be aware of this and adjust your driving and
braking accordingly during this break-in
period.
Excessive high demand braking will cause
correspondingly high brake wear. Please be
attentive to the brake warning lamp in the
instrument cluster and brake condition mes-
sages in the multifunction display. Especial-
ly for high performance driving, it is
important to maintain and have the brake
system checked regularly.

536 Operation
Driving instructions
Catalytic converter
Your Mercedes-Benz is equipped with
monolithic-type catalytic converters, an
important element in conjunction with the
oxygen sensors to achieve substantial con-
trol of the pollutants in the exhaust emis-
sions. Keep your vehicle in proper
operating condition by following our rec-
ommended maintenance instructions as
outlined in your Maintenance Booklet.Emission control
Certain systems of the engine and the
emission control system serve to keep the
toxic components of the exhaust gases
within permissible limits required by law.
These systems will function properly only
when maintained strictly according to fac-
tory specifications. Any adjustments on
the engine should, therefore, be carried
out only by qualified Mercedes-Benz Cen-
ter authorized technicians.
Engine adjustments should not be altered
in any way. The specified service proce-
dures must be carried out regularly accord-
ing to Mercedes-Benz servicing
requirements. For details please refer to
the Maintenance Booklet.
!To prevent damage to the catalytic convert-
ers, only use premium unleaded gasoline in this
vehicle.
Any noticeable irregularities in engine operation
should be repaired promptly. Otherwise, exces-
sive unburned fuel may reach the catalytic con-
verter, causing it to overheat and potentially
start a fire.
Warning!G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.

537 Operation
Driving instructions
Coolant temperature
During severe operating conditions,
e.g. stop-and-go traffic, the coolant tem-
perature may rise close to approximately
248°F (120°C).
The engine should not be operated with
the coolant temperature over 248°F
(120°C). Doing so may cause serious en-
gine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Warning!G
Inhalation of exhaust gas is hazardous to
your health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause un-
consciousness and possible death.
Do not run the engine in confined areas
(such as a garage) which are not properly
ventilated. If you think that exhaust gas
fumes are entering the vehicle while driving,
have the cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one win-
dow fully open at all times.
Warning!G

Driving when your engine is badly over-
heated can cause some fluids, which
may have leaked into the engine com-
partment, to catch fire. You could be se-
riously burned.

Steam from an overheated engine can
cause serious burns and can occur just
by opening the hood. Stay away from
the engine if you see or hear steam com-
ing 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.

542 Operation
Engine compartment
Closing
Let the hood drop from a height of ap-
proximately 1 ft (30 cm).
The hood will lock audibly.
Check to make sure the hood is fully
closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
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 ap-
proximately 30 seconds or even restart af-
ter the engine has been turned off. Stay
clear of fan blades.
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 down. If neces-
sary, call the fire department.
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
cranked manually
Warning!G
When closing the hood, use extreme caution
not to catch hands or fingers. Be careful that
you do not close the hood on anyone.
Make sure that the hood is securely en-
gaged before driving off. Do not continue
driving if the hood can no longer engage af-
ter an accident, for example. The hood could
otherwise come loose while the vehicle is in
motion and endanger you and/or others.


547 Operation
Engine compartment
Active Body Control* (ABC*) fluid level
Regular fluid level check is not required. If
you notice fluid leaks or malfunction mes-
sages in the multifunction display, have an
authorized Mercedes-Benz Center check
the ABC-system.Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze.
When checking the coolant level,

the vehicle must be parked on level
ground

the coolant temperature must be be-
low 158°F (70°C)
The coolant expansion tank is located on
the passenger side of the engine compart-
ment.
Example illustration from S 550
1Cap
2Coolant expansion tank
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 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.

615 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
DISTRONIC PLUS
currently unavailable
See Oper. ManualDISTRONIC Plus* is switched off and is
temporarily unavailable.
DISTRONIC Plus* is deactivated if:

the DISTRONIC Plus* cover in the radia-
tor grille is dirty

the radar sensors* do not sense any
other vehicles or objects, i.e. road sign
or similar to this, for a long time

the system is overheated

its function is impaired as a result of
heavy precipitation or fog

the battery voltage is insufficient
Clean the DISTRONIC Plus* cover in the radiator grille
(
page 589).
Restart the vehicle.
Try activating DISTRONIC Plus* again later.
Wait until the system cools down or the battery recovers.
DISTRONIC Plus* will be operational again without you needing to
restart the engine if:

the dirt (e.g. slush) loosens while you are driving

the system detects that the radar sensors* are fully available
again

the message in the multifunction display disappears
DISTRONIC Plus* is switched off because
the radar sensor system* is temporarily in-
operative due to electromagnetic interfer-
ence near television and radio transmitter
stations, toll stations, speed measuring sys-
tems, etc.Wait until the message in the multifunction display disappears.
DISTRONIC PLUS
inoperativeDISTRONIC Plus* is malfunctioning.
BAS Plus* and PRE-SAFE® Brake* are also
not available.
Contact an authorized Mercedes-Benz Center as soon as pos-
sible.

636 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
Parking brake
See Oper. ManualWhen you engage or release the electronic
parking brake, the red indicator lamp for
the electronic parking brake flashes for
approx.10 seconds. Afterward, it goes out
or lights up continuously. The yellow warn-
ing lamp for the electronic parking brake
lights up.
The electronic parking brake is malfunction-
ing or overheated for example due to over-
or undervoltage.Carefully drive off (page 395).
Contact an authorized Mercedes-Benz Cen-
ter as soon as possible.
In the event of overvoltage or undervoltage:
Remove the cause of the overvoltage or und-
ervoltage, e.g. charge the battery or restart
the engine.
Switch ignition off and back on again, and en-
gage or release electronic parking brake
(
page 395).
If the electronic parking brake still cannot be re-
leased:
Release electronic parking brake mechani-
cally (
page 673).
Contact an authorized Mercedes-Benz Cen-
ter as soon as possible.
(Continued on next page)
(USA only)
(Canada only)

646 Practical hints
What to do if …?
During severe operating conditions,
e.g. stop-and-go traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display Possible cause/consequencePossible solution
Coolant level
Stop vehicle!
Switch engine offThe 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.
Engage the electronic parking brake
(
page 395).
Only start the engine again after the message
disappears. You could otherwise damage the
engine.
Observe the coolant temperature gauge in
the instrument cluster (
page 28).
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 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). Do-
ing so may cause serious engine damage which
is not covered by the Mercedes-Benz Limited
Warranty.