engine overheat MERCEDES-BENZ G500 2003 W463 Owner's Manual

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


open a door


turn on the ignition


press reset knob1


switch on the exterior lamps
You can change the instrument cluster set-
tings in the Instrument cluster submenu of
the control system (
page 122).
Instrument cluster illumination
Use the reset knob to adjust the illumina-
tion brightness for the instrument cluster.
To brighten illumination
Turn reset knob1 in the instrument
cluster clockwise.
The instrument cluster illumination will
brighten.To dim illumination

Turn reset knob1 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 engine hood. Stay away
f r o m t h e e n g i n e i f y o u s e e o r h e a r s t e a m
coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until it
cools down.

198 OperationDriving instructionsPower 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 at an au-
thorized Mercedes-Benz Light Truck Cen-
ter immediately.
All checks and service work on the brake
system should be carried out by an autho-
rized Mercedes-Benz Light Truck Center.
Install only brake pads and brake fluid
recommended by Mercedes-Benz.Warning!
G
When the engine is 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 stop or steer the vehi-
cle.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 73).

199 Operation
Driving instructions
After 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 one 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 145).
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 en-
gine’s braking power (
page 137).
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.


Turn the key to starter switch position0
and remove.


Take the key and lock vehicle when leav-
ing.

211 Operation
Driving instructions
Telephones and two-way radios
Radio transmitters, such as a portable tele-
phone or a citizens band unit should only
be used inside the vehicle if they are con-
nected to an antenna that is installed on
the outside of the vehicle.
Refer to the radio transmitter operation in-
structions regarding use of an external an-
tenna.
Driving abroad
Abroad, there is a widely-spread
Mercedes-Benz service network at your
disposal. If you plan to drive into areas
which are not listed in the index of your
Mercedes-Benz Light Truck Center directo-
ry, you should request pertinent informa-
tion from your 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 Service Booklet.
Warning!
G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system, pos-
sibly resulting in an accident and/or
personal injury.
!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 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.

213 Operation
Driving instructions
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 engine hood. Stay away
f r o m t h e e n g i n e i f y o u s e e o r h e a r s t e a m
coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until it
cools down.

216 OperationEngine compartment
Engine 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 arrow
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. If necessary,
call the fire department.

220 OperationEngine compartmentAdding engine oil
Unscrew cap2 from the filler neck.

Add oil. Be careful not to overfill with
oil.
Be careful not to spill any oil when adding.
Avoid environmental damage caused by oil
coming into contact with the ground or wa-
ter.

Screw cap2 back on the filler neck.
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.
!Excessive 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.
The oil dipstick1 tube allows for drain-
ing of oil by using a suction device.
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 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
1⁄2turn 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.

249 Practical hints
What to do if …
Display
Possible cause
Suggested solution
Category
#
BATTERY/ALTERNATOR
VISIT WORKSHOP!
The battery was charged with a bat-
tery charger or jump started.

Have the battery checked at a
service station.
2
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. Oth-
erwise the engine will overheat
due to an inoperative water
pump which may result in seri-
ous engine damage not cov-
ered by the Mercedes-Benz
Limited Warranty. Notify an
authorized Mercedes-Benz
Light Truck Center.
If it is intact:

Turn off unnecessary electric
consumers.

Drive immediately to the near-
est authorized Mercedes-Benz
Light Truck Center.

251 Practical hints
What to do if …
Display
Possible cause
Suggested solution
Category
B
COOLANT
CHECK LEVEL!
The coolant level is too low.

Add coolant (
page 220).

If you have to add coolant fre-
quently, have the cooling sys-
tem checked by an authorized
Mercedes-Benz Light Truck
Center.
2
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 serious
engine damage.
Observe the coolant temperature dis-
play (
page 108).

252 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
Possible cause
Suggested solution
Category
B
COOLANT
STOP, ENGINE OFF!
The coolant is too hot.

Stop the vehicle and turn off
the engine.

Only start the engine again af-
ter the message disappears.
You could otherwise damage
the engine.
1
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.
!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.