2003 MERCEDES-BENZ ML500 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 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 206).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
Center.
If no damage can be determined on the


major assemblies


fuel system


engine mount:

Start the engine in the usual manner.

125 Controls in detail
Automatic climate control
Automatic climate control panel in the front
Item
1
Thumbwheel center air outlet
2
Center air outlet, adjustable
3
Defroster air outlet windshield
4
Thumbwheels side air outlet
5
Side air outlet, adjustable
6
Footwell air outlet
7
Automatic climate control
Item
1
Air volume control
2
Defrosting
3
Air recirculation
4
Temperature control
5
Automatic control (temperature, air
distribution, air volume)
6
AC
OFF
(AC cooling on/off), econo-
my mode
Residual heat/ventilation
7
Interior temperature sensor
8
Air distribution control
9
Rear window defroster
10
Rear passenger compartment venti-
lation on/off

126 Controls in detailAutomatic climate controlThe automatic climate control is operation-
al whenever the engine is running. You can
operate the climate control system in ei-
ther the automatic or manual mode. The
system cools or heats the interior depend-
ing on the selected interior temperature
and the current 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.
Automatic mode
Switching on
Briefly press button
U

(
page 125).
The indicator lamp lights up. The tem-
perature, air volume and distribution
are controlled automatically.

Adjust the temperature with the tem-
perature control4 (
page 125).
Temperature control is switched off in
the extreme position (blue or red dot).
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.
iSevere conditions (e.g. strong air pollu-
tion) may require replacement of the fil-
ter before its scheduled interval. A
clogged filter will reduce the air volume
to the interior.
If 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.
Do not touch the interior temperature
sensor to maintain a precise tempera-
ture.
The set value is indicated by a lighted
segment on the control wheels.

129 Controls in detail
Automatic climate control
Activating
Press button
O
(page 125).
The indicator lamp on the button lights
up.
Deactivating

Press button
O
(page 125).
The indicator lamp on the button goes
out.
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 automatic
climate control system. The air in the vehi-
cle will then no longer be cooled or dehu-
midified.
Press button
°
(page 125).
The indicator lamp on the button
°

lights up.
iTo achieve the fastest possible cooling
of the interior, the automatic climate
control automatically switches to air
recirculation. The indicator lamp in the
button
O
is not illuminated when
the system automatically switches to
air recirculation.
iThe air recirculation mode is activated
automatically after

30 minutes if the automatic climate
control is switched on


after five minutes if the air condi-
tioning is switched off


after five minutes if the outside
temperature is above approximate-
ly 45°F (7 °C)
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.

131 Controls in detail
Automatic climate control
Rear window defroster
The rear window defroster uses a large
amount of power. To keep the battery
drain to a minimum, switch off the defrost-
er as soon as the rear window is clear. The
defroster is automatically deactivated af-
ter approximately 6 to 17 minutes of oper-
ation depending on the outside
temperature.
Activating
Switch ignition on.

Press button
F
(page 125).
The indicator lamp on the button lights
up.
Deactivating

Press button
F
again.
The indicator lamp on the button goes
out.Rear passenger compartment ventila-
tion and rear automatic climate control
Deactivating
For an improved cooling or heating output
in the front passenger compartment, you
can switch off the rear passenger compart-
ment ventilation.
Press button
§
(page 125).
The indicator lamp on the button lights
up.
The operation of the rear automatic cli-
mate control and the fresh air supply to
the rear compartment is shut off.
Activating

Press button
§
again.
The indicator lamp on the button goes
out.
The rear automatic climate control
switches to automatic mode and fresh
air enters the rear compartment.
Warning!
G
Any accumulation of snow and ice should be
removed from the rear window before driv-
ing. Visibility could otherwise be impaired,
endangering you and others.!If the rear window defroster switches
off too soon and the indicator lamp
starts blinking, this means that too
many electrical consumers are operat-
ing simultaneously and there is insuffi-
cient voltage in the battery. The system
responds automatically by deactivating
the rear window defroster.
As soon as the battery has sufficient
voltage, the rear window defroster au-
tomatically turns itself back on.

206 OperationEngine compartmentTransmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Light
Truck Center check the automatic trans-
mission.Coolant
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool. 1Cap
2COLD LEVEL mark
The coolant level should reach the COLD
LEVEL mark2 in the reservoir.

Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.
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 gauge indi-
cates 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 ½ 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.
iIf the engine is already at its regular op-
erating temperature, the coolant may
be approximately 0.6 in (1.5 cm) above
the COLD LEVEL mark.


230 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
/
The yellow coolant warning lamp
lights up when the engine is run-
ning.
The coolant is to hot.
The coolant level is too low.

Stop as soon as possible and allow
the engine and coolant to cool down.

Check the coolant level and add
coolant if necessary (
page 206).
If the warning lamp lights up frequently, there
is a leak in the cooling system.

Have the cooling system checked by
an authorized Mercedes-Benz Light
Truck Center.
The coolant temperature gauge is above
248 °F (120 °C).
The coolant level is too low.

Stop as soon as possible and allow
the engine and coolant to cool down.

Add coolant to prevent engine from
overheating (
page 206).
If the coolant level is correct, the electrical
radiator fan may be broken.

If the coolant temperature is below
the red zone, drive on to the nearest
authorized Mercedes-Benz Light
Truck Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.

285 Technical data
Fuels, coolants, lubricants etc.
Model
Capacity
Fuels, coolants, lubricants etc.
Cooling system
approx. 12.7 US qt (12.0 l)
MB Anticorrosion / Antifreeze
Fuel tank
ML 320, ML 350,
ML 500
22.0 US gal (83.0 l)
Premium unleaded gasoline:
Posted Octane 91 (Avg. of 96 RON/86 MON
ML 55 AMG
25.0 US gal (95.0 l)
Premium unleaded gasoline:
Posted Octane 91 (Avg. of 96 RON/86 MON
including a reserve of
approx. 3.2 US qt (12.0 l)
Air conditioning system
R-134a refrigerant and special PAG lubricant
oil (never R-12)
Windshield washer and
headlamp cleaning sys-
tem
8.0 US qt (7.6 l)
MB Windshield Washer Concentrate
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 290).