engine overheat MERCEDES-BENZ G55AMG 2005 W463 Owner's Manual

120 Controls in detailInstrument clusterA full view illustration of the instrument
cluster can be found in the “At a glance”
section of this manual (
page 24).
1Reset button
The instrument cluster is activated when
you:


Open a door.


Switch on ignition.


Press reset button1.


Switch on the exterior lamps.
You can change the instrument cluster set-
tings in the Instrument cluster submenu of
the control system (
page 135).
Instrument cluster illumination
Use the reset button to adjust the illumina-
tion brightness for the instrument cluster.
To brighten illumination
Turn reset button1 in the instrument
cluster clockwise.
The instrument cluster illumination will
brighten.To dim illumination

Turn reset button1 in the instrument
cluster counterclockwise.
The instrument cluster illumination will
dim.
Coolant temperature display
iThe instrument cluster illumination is
dimmed or brightened automatically to
suit ambient 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 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.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.

217 Operation
Driving instructions
Power assistanceBrakesTo 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.If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on and there is no audible warn-
ing (EBB), the brake fluid level in the
reservoir is too low.
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the res-
ervoir.
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Light Truck Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Light Truck Center.
Install only brake pads and brake fluid
recommended by Mercedes-Benz.Warning!
G
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the ve-
hicle.Warning!
G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components
or salty road conditions, the first braking ac-
tion may be somewhat reduced and in-
creased 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 acci-
dent.
!Be very careful not to endanger other
road users when you apply the brakes.
Refer to the description of the Brake
Assist System (BAS) (
page 82).

218 OperationDriving instructionsAfter hard braking, it is advisable to drive
on for some time, rather than immediately
parking, so the air stream will cool down
the brakes faster.
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the oper-
ating temperature has been reached.
When starting off on a slippery surface, do
not allow a drive wheel to spin for an ex-
tended period with the ESP switched off.
Doing so may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
To ensure sufficient traction during
off-road driving, activate differential locks
as needed (
page 158).
Parking
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 selecting gear range3,2 or1 on the
automatic transmission to use the
engine’s braking power (
page 150).
This helps prevent overheating of the
brakes and reduces brake pad wear.
Warning!
G
Do not park this vehicle in areas where com-
bustible 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.
To reduce the risk of personal injury as a re-
sult of vehicle movement, before
turning off
the engine and leaving the vehicle always:


Keep right foot on brake pedal.


Pull the parking brake lever up as many
notches as possible.


Move the selector lever to positionP.


Slowly release brake pedal.


When parked on an incline, turn front
wheel towards the road curb.

232 OperationDriving instructionsDriving abroad
Abroad, there is an extensive
Mercedes-Benz service network at your
disposal. If you plan to drive into areas
which are not listed in the index of an
Mercedes-Benz Light Truck Center directo-
ry, you should request pertinent informa-
tion from an authorized Mercedes-Benz
Light Truck Center.
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.
!To prevent damage to the catalytic con-
verters, use only premium unleaded
gasoline in this vehicle.
Any noticeable irregularities in engine
operation should be repaired promptly.
Otherwise, excessive unburned fuel
may reach the catalytic converter,
causing it to overheat and potentially
start a fire.

234 OperationDriving instructionsCoolant temperature
During severe operating conditions, e.g.
stop-and-go city traffic, the coolant tem-
perature may rise to approx. 248°F
(120°C).
The engine should not be operated with
the coolant temperature above 248°F
(120°C). Doing so may cause serious en-
gine damage which is not covered by the
Mercedes-Benz Limited Warranty.
iExcessive coolant temperatures trigger
a warning message in the multifunction
display (
page 306).
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.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.

238 OperationEngine compartmentHood
Opening
The pull release lever is under the driver’s
side of the instrument panel.
1Release lever

Pull release lever1 upward.
The hood is unlocked.
2Safety hook

Lift hood up slightly.

Pull safety hook2 in direction of ar-
row and open hood.
Warning!
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.
!To avoid damage to the windshield wip-
ers or hood, open the hood only with
wipers in parked position.
Warning!
G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running. Make sure the hood is
properly closed before driving. When closing
the hood, use extreme caution not to catch
hands or fingers.
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 display 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.

244 OperationEngine compartment
Screw oil filler cap2 back on filler
neck.
For more information on engine oil, see the
“Technical data” section (
page 374) and
(
page 375).
Transmission fluid level
The transmission fluid level does not need
to be checked. The transmission has a per-
manent supply of automatic transmission
fluid.
If you notice transmission fluid loss or gear
shifting malfunctions, have an authorized
Mercedes-Benz Light Truck Center check
the automatic transmission.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 engine must be cool. The coolant
level should reach the COLD LEVEL
mark in the reservoir.
!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.
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 display in-
dicates 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
1/2turn 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.


302 Practical hintsWhat to do if …Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
BATTERY/ALTERNATOR
VISIT WORKSHOP!
The battery was charged with a battery
charger or jump started.

Have the battery checked at a service
station.
The battery is no longer charging.
Possible causes:

alternator malfunctioning


broken poly-V-belt

Stop immediately and 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 serious engine damage not
covered by the Mercedes-Benz Limited
Warranty. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:

Turn off unnecessary electric consum-
ers.

Drive immediately to the nearest
authorized Mercedes-Benz Light Truck
Center.
UNDERVOLTAGE
ENGINE ON!
The battery has insufficient voltage.

Start the engine.

305 Practical hints
What to do if …
Display symbol
Display message
Possible cause
Possible solution
B
COOLANT
CHECK LEVEL!
The coolant level is too low.

Add coolant (
page 244).

If you have to add coolant frequently,
have the cooling system checked by
an authorized Mercedes-Benz Light
Truck 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 Limited
Warranty.
Do not drive without sufficient amount
of coolant in the cooling system. The
engine will overheat causing serious
engine damage.
Observe the coolant temperature dis-
play (
page 120).

306 Practical hintsWhat 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 symbol
Display message
Possible cause
Possible solution
Ï
COOLANT
STOP, ENGINE OFF!
The coolant is too hot.

Stop the vehicle and turn off the en-
gine.

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 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
engine damage which is not covered by
the Mercedes-Benz Limited Warranty.