2003 MERCEDES-BENZ G55AMG cooling

49 Getting started
Driving
Problems while driving
The engine runs erratically and misfires

An ignition cable may be damaged.


The engine electronics may not be op-
erating properly.


Unburned gasoline may have entered
the catalytic converter and damaged it.

Give very little gas.

Have the problem repaired by an au-
thorized Mercedes-Benz Light Truck
Center as soon as possible.The coolant temperature is over 248°F
(120°C)
The coolant is too hot and is no longer
cooling the engine.

Stop the vehicle as soon as possible
and turn off the engine. Allow engine
and coolant to cool.

Check the coolant level and add cool-
ant if necessary (
page 220).In case of accident
If the vehicle is leaking gasoline:

Do not start the engine under any cir-
cumstances.

Notify local fire and/or police authori-
ties.
If the extent of the damage cannot be de-
termined:

Notify an authorized Mercedes-Benz
Light Truck Center.
If no damage can be determined on the


major assemblies


fuel system


engine mount:

Start the engine in the usual manner.
iExcessive coolant temperatures trigger
a warning message in the multifunction
display (
page 252).

151 Controls in detail
Climate control
Climate control panel
1
Windshield defroster outlets
2
Center air vent, adjustable
3
Thumbwheel for center air vent
4
Side air vent, adjustable
5
Side defroster outlet, fixed
6
Thumbwheel for side air vent
7
Footwell air vents
8
Climate control panel
iFor draft-free ventilation, move the slid-
ers for the center air vents to the mid-
dle position.
1
Air volume
2
Temperature control, left
3
Temperature control, right
4
Air distribution control switch
5
Rear window defroster
6
AC cooling on / off (AC
OFF
)
Residual engine heat utilization
7
Air distribution and air volume (au-
tomatic mode)
8
Air recirculation
9
Defrosting

152 Controls in detailClimate controlThe climate control is operational whenev-
er the engine is running. You can operate
the climate control system in either the au-
tomatic or manual mode. The system cools
or heats the interior depending on the se-
lected interior temperature and the cur-
rent outside temperature.
Nearly all dust particles, pollutants and
odors are filtered out before outside air en-
ters the passenger compartment through
the air distribution system.
The air conditioning will not engage (no
cooling) if the AC
OFF
mode is selected
(
page 157).
Setting the temperature
Use temperature controls2 and3 to sepa-
rately adjust the air temperature on each
side of the passenger compartment. You
should raise or lower the temperature set-
ting in small increments, preferably start-
ing at 72°F (22°C).Increasing

Turn the temperature control a few de-
grees to the right.
The climate control system will corre-
spondingly adjust the interior air tem-
perature.
Decreasing

Turn the temperature control a few de-
grees to the left.
The climate control system will corre-
spondingly adjust the interior air tem-
perature.
Warning!
G
Follow the recommended settings for heat-
ing and cooling given on the following pag-
es. Otherwise the windows could fog up,
impairing visibility and endangering you and
others.
iIf the vehicle interior is hot, ventilate
the interior before driving off.
Keep the air intake grille in front of the
windshield free of snow and debris.iWhen operating the climate control
system in automatic mode, you will
only rarely need to adjust the tempera-
ture, air volume and air distribution.

157 Controls in detail
Climate control
Air conditioning
The air conditioning is operational while
the engine is running and cools the interior
air to the temperature set by the operator.
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the climate
control system. The air in the vehicle will
then no longer be cooled or dehumidified.
Press button
°
(page 151).
The indicator lamp on the button
°

lights up.Activating
Moist air can fog up the windows. You can
dehumidify the air with the air conditioner.

Press button
°
again (
page 151).
The indicator lamp on the button
°

goes out.
The air conditioner uses the refrigerant
R134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.Rear passenger compartment adjust-
able air vents
1Air volume control for center air vents
2Left center air vent, adjustable
3Right center air vent, adjustable
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.
!If the
°
button on the climate con-
trol panel starts to blink, this indicates
that the air conditioner is losing refrig-
erant. The compressor has turned itself
off. The air conditioner cannot be
turned on again.


Have the air conditioner checked at
the nearest authorized
Mercedes-Benz Center.

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.

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).

253 Practical hints
What to do if …
Display
Possible cause
Suggested solution
Category
B
COOLANT
STOP, ENGINE OFF!
The poly-V-belt could be broken.

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
damage to the engine. Notify
an authorized Mercedes-Benz
Light Truck Center.
If it is in order:

Do not continue to drive the
vehicle with this message dis-
played. Doing so could result
in serious engine damage that
is not covered by the
Mercedes-Benz Limited War-
ranty.
1
COOLANT
VISIT WORKSHOP!
The cooling fan for the coolant is
malfunctioning.

Observe the coolant tempera-
ture display (
page 108).

Have the fan replaced as soon
as possible.
2

317 Technical data
Fuels, coolants, lubricants etc.
Engine oils
Engine oils are specifically tested for their
suitability in our engines. Therefore, use
only engine oils recommended by
Mercedes-Benz. Information on recom-
mended brands is available in the Factory
Approved Service Products pamphlet, or at
your authorized Mercedes-Benz Light
Truck Center.
Please follow FSS and Service Booklet rec-
ommendations for scheduled oil changes.
F ai lu re to d o s o could res ul t in engi ne da m -
age not covered by the Mercedes-Benz
Limited Warranty.
Engine oil additives
Do not blend oil additives with engine oil.
They may be harmful to the engine opera-
tion.
Damage or malfunctions resulting from
blending oil additives are not covered by
the Mercedes-Benz Limited Warranty.
Air conditioning refrigerant
R-134a (HFC) refrigerant and special PAG
lubricating oil is used in the air condition-
ing system.
Never use R-12 (CFC) or mineral-based lu-
bricating oil, otherwise damage to the
system will occur.
Model
Capacity
Fuels, coolants, lubricants etc.
Cooling system
approx. 12.7 US qt (12.0 l)
MB Anticorrosion/Antifreeze
Air conditioning system
R-134a refrigerant and
special PAG lubricant oil (never R-12)
Windshield/rear window washer system
and headlamp cleaning system
approx. 7.9 US qt (7.5 l)
MB Windshield Washer Concentrate
and water
1
1Use MB Windshield Washer Concentrate “S” and water for temperatures above freezing or MB Windshield Washer Concentrate “S” and commercially available pre-
mixed windshield washer solvent / antifreeze for temperatures below freezing. Follow suggested mixing ratios (
page 321).