2002 MERCEDES-BENZ G500 engine overheat

123 Coolant temperature gauge
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Coolant temperature gauge
Turn the electronic key in starter switch to position 1
or 2.
Call up the trip odometer and main odometer by
pressing button è or ÿ on the multifunction
steering wheel. See page 94.
Press button j or k until the coolant
temperature gauge appears.During severe operating conditions and stop-and-go city
traffic or uphill driving, the coolant temperature may
rise close to 120
°C.
The engine should not be operated with the coolant
temperature above 120
°C. Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Note:
Excessive coolant temperatures trigger a warning
message in the multifunction display. See page 281.
0
60
40100
120
140
mph
2080
P54.30-5171-26
Wa r n i n g !
• Driving when your engine is badly 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 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.
J_G463.book Seite 123 Mittwoch, 19. September 2001 8:06 08

202 Catalytic converter
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Catalytic converter
Your Mercedes-Benz is equipped with monolithic type
catalytic converters, an important element in
conjunction with the oxygen sensors to achieve
substantial control of the pollutants in the exhaust
emissions. Keep your vehicle in proper operating
condition by following our recommended maintenance
instructions as outlined in your Service Booklet.Caution!
To prevent damage to the catalytic converters, 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, which could start a fire.
Wa r n i n g !
As with any vehicle, do not idle, park or operate
this vehicle in areas where combustible 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.
J_G463.book Seite 202 Mittwoch, 19. September 2001 8:06 08

217 Driving instructions
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Power assistance
BrakesExcessive use of road salt and other snow melting
chemicals spread on roads during the winter months
may cause a build up of moisture or residue to form on
the braking components. This build up or residue could
cause light corrosion of the braking components if the
vehicle is parked with the brakes cold. Apply steady and
even braking pressure when stopping the vehicle to
warm up and dry the brake components.
Important!
Please pay attention to the function of the brake assist
system (BAS), see page 237.
The condition of the parking brake system is checked
each time the vehicle is in the shop for the required
maintenance service.
If the parking brake is released and the brake warning
lamp in the instrument cluster stays on and there is no
audible warning (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 reservoir.
Have the brake system inspected at an authorized
Mercedes-Benz Light Truck Center immediately.
Wa r n i n g !
When the engine is not running, the brake and
steering systems are without power assistance.
Under these circumstances, a much greater effort is
necessary to stop or steer the vehicle.Wa r n i n g !
After driving in heavy rain for some time without
applying the brakes or through water deep enough
to wet brake components or salty road conditions,
the first braking action may be somewhat reduced
and increased pedal pressure may be necessary to
obtain expected braking effect. Be sure to 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 effectiveness. It may
not be possible to stop the vehicle in sufficient time
to avoid an accident.
J_G463.book Seite 217 Mittwoch, 19. September 2001 8:06 08

218 Driving instructions
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
All checks and service work on the brake system should
be carried out by an authorized Mercedes-Benz Light
Truck Center.
Install only brake pads and brake fluid recommended by
Mercedes-Benz.
Caution!
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.
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 service 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 operating temperature has been
reached.
When starting of f on a slippery surface, do not allow one
drive wheel to spin for an extended period with the ESP
switched off. Doing so may cause serious damage to the
drive train which is not covered by the Mercedes-Benz
Limited Warranty.
To ensure sufficient traction during off-road driving,
activate differential locks as needed, see page 253.
Wa r n i n g !
If other than recommended brake pads are
installed, or other than recommended brake fluid
is us ed, t he b ra ki ng properti es of the vehic l e c an be
degraded to an extent that safe braking is
substantially impaired. This could result in an
accident.
J_G463.book Seite 218 Mittwoch, 19. September 2001 8:06 08

274 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
BATTERY / ALTERNATOR
* C = Category, see page 272
This message indicates a malfunction which must be
repaired immediately.
It may indicate that the poly-V-belt has broken. Should
this condition occur, the poly-V-belt must be replaced
before continuing to operate the vehicle. Otherwise, the
engine will overheat due to an inoperative water pump
which may result in damage to the engine.
Do not continue to drive the vehicle with this message
displayed.
Doing so could result in serious engine damage that is
not covered by the Mercedes-Benz Limited Warranty.
Line 1 Line 2 C*
BATTERY/ALTERNATOR VISIT WORKSHOP! 2
J_G463.book Seite 274 Mittwoch, 19. September 2001 8:06 08

280 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
COOLANT (coolant level)
* C = Category, see page 272When this message appears while driving, the coolant
level has dropped below the required level. If no leaks
are noticeable and the engine temperature does not
increase, continue to drive to the nearest service station
and have coolant added to the coolant system.The low engine coolant level warning should not be
ignored. Extended driving with the symbol displayed
may cause serious engine damage not covered by the
Mercedes-Benz Limited Warranty.
In cases of major or frequent minor coolant loss, have
the cooling system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
Note:
Do not drive without coolant in the cooling system. The
engine will overheat causing major engine damage.
Monitor the coolant temperature gauge while driving,
see page 123.
See page 306 for instructions on topping up the coolant.Line 1 Line 2 C*
COOLANT CHECK LEVEL! 2
Wa r n i n 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.
J_G463.book Seite 280 Mittwoch, 19. September 2001 8:06 08

281 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index COOLANT (coolant temperature)
* C = Category, see page 272
1 This may indicate that the poly-V-belt has broken. Should this
con dition o ccur, the poly-V-belt must be repla ced befo re co ntin uin g
to operate the vehicle. Otherwise, the engine will overheat due to
an inoperative water pump which may result in damage to the
engine. Do not continue to drive the vehicle with this message
displayed. Doing so could result in serious engine damage that is
not covered by the Mercedes-Benz Limited Warranty.
2 The cooling fan for the coolant is faulty. Observe the coolant
temperature gauge. See page 123
During severe operating conditions and stop-and-go city
traffic, the coolant temperature may rise close to 120
°C.
The engine should not be operated with the coolant
temperature above 120
°C. Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Line 1 Line 2 C*
COOLANT STOP, ENGINE OFF!
1
1
COOLANT VISIT WORKSHOP!
2
2
Wa r n i n g !
Driving when your engine is badly 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 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.
J_G463.book Seite 281 Mittwoch, 19. September 2001 8:06 08

303 Engine compartment
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index
Wa r n i n g !
To help prevent personal injury, stay clear of
moving parts when the hood is open and the engine
is running. Be sure the hood is properly closed
before driving. When closing hood, use extreme
caution not to catch hands or fingers.The radiator fan may continue to run for
approximately 30 seconds or even restart after the
engine has been turned off. Stay clear from fan
blades.The engine is equipped with a transistorized
ignition system. Because of the high voltage it is
dangerous to touch any components (ignition 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.
If you see flames, steam or smoke coming from the
engine compartment, or if the coolant temperature
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 a fire department.
J_G463.book Seite 303 Mittwoch, 19. September 2001 8:06 08