2008 MERCEDES-BENZ GL320 cooling system

240 Controls in detail
3-zone automatic climate control*
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 button9 (page 230).
The indicator lamp on the button goes
out. The cooling function switches off
after a short delay.
Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.
Press button9 again.
The indicator lamp on the button
comes on.
The air conditioning uses the refrigerant
R-134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.Using driver-side settings for all tem-
perature zones
You can use the settings of the driver’s
side, such as temperature, air volume and
air distribution, for all temperature zones.
These settings only need to be made once
and the automatic climate control system
will automatically regulate the settings for
all temperature zones quickly and comfort-
ably.Activating
Adjust the temperature, air volume and
air distribution (
page 230).
Press button; (page 230).
The indicator lamp on the button
comes on.
The driver-side settings are used for all
temperature zones.
Deactivating
Press button; (page 230) again.
The indicator lamp on the button goes
out.
!If the air conditioning cannot be turned on
again, this indicates that the air conditioning is
losing refrigerant. The compressor has turned
off.
Have the air conditioning checked at the nearest
authorized Mercedes-Benz Light Truck Center.
iIf you manually set the temperature, air vol-
ume or air distribution for the passenger side or
the rear passenger compartment when the
MONO setting is active, the MONO setting will
be switched off.
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382 Operation
Engine compartment
The coolant expansion tank is located on
the driver’s side of the engine compart-
ment.
1Cap
2Coolant expansion tank
3Indicator wall
4Coolant levelUsing a rag, turn cap1 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning cap1 counterclock-
wise and remove it.
Coolant level4 is correct if the level:

for cold coolant: reaches the top of
indicator wall3 visible through the
filling opening

for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap1.
For more information on coolant, see
“Coolants” (
page 567).
Warning!G
In order to avoid potentially 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
indicates 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 1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out
under pressure.

Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene
glycol which may burn if it comes into
contact with hot engine parts.
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472 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
B Top Up Coolant
See Operator’s ManualThe coolant level is too low.Add coolant (page 381).
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 major engine damage.
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563 Technical data
Fuels, coolants, lubricants
ModelCapacityFuels, coolants, lubricants, etc.
Front wheel hubsAll modelsapprox. 1.5oz (43g) eachHigh temperature roller bearing grease
Brake systemAll models-MB Brake Fluid (DOT 4+)
Cooling systemGL 320 CDIapprox. 10.0 US qt (9.5 l)MB Anticorrosion/Antifreeze
GL 450approx. 10.6 US qt (10.0 l)MB Anticorrosion/Antifreeze
GL 5501approx. 12.7 US qt (12.0 l)MB Anticorrosion/Antifreeze
Fuel Tank
including a reserve ofAll models26.4 US gal (100.0 l)
approx. 3.4 US gal (13.0 l)Gasoline engine:
Premium unleaded gasoline:
Minimum Posted Octane 91
(Avg. of 96 RON/86 MON)
Diesel engine:
ULTRA-LOW SULFUR HIGHWAY DIESEL FUEL
(15 ppm SULFUR MAXIMUM)
Air conditioning systemAll models-R-134a refrigerant and special PAG lubricant oil
(never R-12)
Windshield washer system
and headlamp cleaning
system*All models8.1 US qt (7.7 l)MB Windshield Washer Concentrate2
1Data preliminary.2Use MB Windshield Washer Concentrate “MB SummerFit” and water for temperatures above freezing or MB Windshield Washer Concentrate “MB SummerFit” and
commercially available premixed windshield washer solvent/antifreeze for temperatures below freezing. Follow suggested mixing ratios (page 569).
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567 Technical data
Fuels, coolants, lubricants
Coolants
The engine coolant is a mixture of water
and anticorrosion/antifreeze, which
provides:

Corrosion protection

Freeze protection

Boiling protection (by increasing the
boiling point)
The cooling system was filled at the factory
with a coolant providing freeze protection
to approximately -35°F (-37°C) and corro-
sion protection.If the antifreeze mixture is effective to
-35°F (-37°C), the boiling point of the cool-
ant in the pressurized cooling system is
reached at approximately 266°F (130°C).
The coolant solution must be used year
round to provide the necessary corrosion
protection and increase boil-over protec-
tion. Refer to Maintenance Booklet for
replacement interval.
Coolant system design and coolant used
determine the replacement interval. The
replacement interval published in the
Maintenance booklet is only applicable if
MB 325.0 Anticorrosion/Antifreeze solu-
tion or other Mercedes-Benz approved
products of equal specification are used to
renew the coolant concentration or bring it
back up to the proper level.
For information on other Mercedes-Benz
approved products of equal specification,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Light Truck
Center.To provide important corrosion protection,
the solution must be at least 50% anticor-
rosion/antifreeze (equivalent to freeze
protection to approximately -35°F
[-37°C]). If you use a solution that is more
than 55% anticorrosion/antifreeze (freeze
protection to approximately -49°F
[-45°C]), the engine temperature will
increase due to the lower heat transfer
capability of the solution. Therefore, do not
use more than this amount of anticorro-
sion/antifreeze.
If the coolant level is low, water and
MB 325.0 Anticorrosion/Antifreeze
should be used to bring it up to the proper
level (have cooling system checked for
signs of leakage). Please make sure the
mixture is in accordance with label instruc-
tions.
The water in the cooling system must meet
minimum requirements, which are usually
satisfied by normal drinking water. If you
are not sure about the water quality, con-
sult an authorized Mercedes-Benz Light
Truck Center.
!Add premixed coolant solution only. Adding
water and MB 325.0 Anticorrosion/Antifreeze
separately from each other, could cause engine
damage not covered by the
Mercedes-Benz Limited Warranty.
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571 Index
A
ABS 101
Indicator lamp 436
Off-road - ABS 102
ABS, ESP
®
Messages in the multifunction
display 451
Accelerator position, automatic
transmission 195
Accessory weight 415
Accident 66
Active head restraint 90, 133, 499
Adaptive Damping System (ADS)* 278
Air bags 76
Children 77, 91
Front passenger front air bag off
indicator lamp 31, 32, 85
Front, Driver 79
Front, Passenger 79
Occupant Classification System
(OCS) 81
Safety guidelines 78
Side impact (front and rear*) 80
Window curtain 80Air conditioning refrigerant 564
Air conditioning system see
Climate control or
Automatic climate control (3-zone)*
Air conditioning, Cooling 224, 239
Air distribution, Front 219, 234
Air distribution, Rear 227, 243
Air pressure see Tire inflation pressure
Air recirculation mode 222, 237
Air suspension program 278
Adaptive Damping System
(ADS)* 278
Messages in the multifunction
display 486
Vehicle level control 279
Air vents 227
Air vents*, Rear 245
Air vents, Front 220, 234
Air volume 220, 235
Alarm system see Anti-theft systems
Alignment bolt (vehicle tool kit) 492, 524
Anticorrosion/antifreeze 563, 568
Antiglare, Interior rear view mirror 208Antiglare, Rear view mirrors* 208
Antilock Brake System see ABS
Anti-theft systems 110
Anti-theft alarm system 109, 110
Immobilizer 109
Aquaplaning see Hydroplaning
Armrest storage/telephone*
compartment
Front 317
Ashtrays (Depending on
vehicle configuration) 321
Aspect ratio 415
ATF 381
Attaching a trailer 366
AUDIO menu 164
Audio menu
CD operation 165
Radio operation 164
Satellite radio* operation 164
Auto-dimming*, Rear view mirrors 208
Automatic central locking,
Control system 180
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572 Index
Automatic climate control (3-zone)* 228
Air conditioning refrigerant 563
Air conditioning, Cooling 239, 240
Air distribution, Front 234
Air distribution, Rear 243
Air recirculation mode 237
Air vents*, second-row seats 245
Air vents*, third-row seats 245
Air vents, Front 234
Air volume 235
Control panel, Front 230
Control panel, Rear 241
Deactivating system 232
Defogging 235
Defrosting 235
Maximum cooling, MAXCOOL 237
Rear passenger compartment 241
Rear window defroster 212
Residual engine heat (REST) 241
Using driver-side settings for
all temperature zones 240Automatic headlamp mode 144
Automatic lighting control, Interior
lighting 150
Automatic locking when driving 128
Automatic transmission 56
Accelerator position 195
Emergency operation
(limp-home mode) 200
Gear ranges 197
Gear selector lever 56, 189
Gear selector lever position 192
Gear shifting malfunctions 200
Hill start assist system 196
Kickdown 196
Shifting procedure 192
Starting the engine 56
Steering wheel gearshift control 198
Towing a trailer 197
Transmission fluid level 381
Transmission positions 193
Automatic Transmission Fluid see ATFB
Backrest
Seat 46
Seat, Lumbar support 137
Seat, Multicontour* 138
Backup lamps
Messages in the multifunction
display 477
Replacing bulbs 511
Bar 416
BAS 103
Lamps in instrument cluster 436
Messages in the multifunction
display 451
Batteries, SmartKey
Check lamp 112, 115
Checking battery condition 120
Messages in the multifunction
display 466
Replacing 502
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574 Index
Children in the vehicle 91
Air bags 77, 91
Blocking rear door window
operation 98
Indicator lamp, Front passenger front
air bag 85
Infant and child restraint systems 86,
92
LATCH-type child seat anchors 95
Occupant Classification System
(OCS) 81
Cigarette lighter
(Depending on vehicle
configuration) 323
Climate control 214
Air conditioning refrigerant 563
Air conditioning, Cooling 224, 225
Air distribution, Front 219
Air distribution, rear 227
Air recirculation mode 222
Air vents*, second-row seats 220
Air vents, Front 220
Air volume 220
Control panel*, Rear 226
Control panel, Front 216
Deactivating system 218Defogging 222
Defrosting 221
Rear window defroster 212
Residual engine heat (REST) 225
Clock 27, 174
Cloth upholstery, Cleaning and
care of 434
Cockpit 24
Cockpit Management and Data System
see COMAND System
Cold tire inflation pressure 416
Collapsible wheel chock 494
COMAND System see separate operating
instructions
Combination switch 61, 62, 64, 147
Compass 344
Adjustment 178
Calibration 179
Calling up the compass 344
Control and operation of radio
transmitters 370
Control system 155
Multifunction display 155
Multifunction steering wheel 156
Resetting to factory default 169Control system menus 155
AUDIO 164
DISTRONIC* (Canada only) 167
NAV* 166
Off-road 166
Settings 168
Standard display 162
TEL* 186
Trip computer 184
Vehicle configuration 182
Vehicle status message memory 167
Control system submenus 159, 161, 171
Comfort* 181
Instrument cluster 172, 173
Lighting 175
Time/Date 174
Vehicle 178
Coolant 381, 567
Anticorrosion/antifreeze mixing ratio
and quantity 568
Capacities 562
Checking coolant level 376, 381
Messages in the multifunction
display 470, 472
Temperature 372
Temperature display 162
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