coolant temperature MERCEDES-BENZ R350 2008 W251 Owner's Manual

Contents
Oxidation catalyst
(diesel engine).............................. 349
Emission control .......................... 350
Coolant temperature .................... 350
At the gas station .............................. 352
Refueling ...................................... 352
Check regularly and before a
long trip........................................ 354
Engine compartment ......................... 356
Hood ............................................ 356
Engine oil ..................................... 358
Transmission fluid level ................ 360
Coolant level ................................ 360
Windshield/rear window washer
system and headlamp cleaning
system* ....................................... 362
Tires and wheels ................................ 363
Important guidelines .................... 363
Tire care and maintenance........... 364
Direction of rotation ..................... 365
Loading the vehicle ...................... 366
Recommended tire inflation
pressure ....................................... 371
Checking tire inflation pressure ... 373
Tire labeling.................................. 384
Load identification ....................... 388DOT, Tire Identification Number
(TIN) .............................................. 388
Maximum tire load ........................ 390
Maximum tire inflation pressure ... 390
Uniform Tire Quality Grading
Standards (U.S. vehicles) .............. 391
Tire ply material ............................ 393
Tire and loading terminology......... 393
Rotating tires ................................ 396
Winter driving ..................................... 398
Winter tires ................................... 398
Snow chains.................................. 399
Maintenance....................................... 400
Maintenance service indicator
message ....................................... 400
Calling up the maintenance
service indicator display ............... 402
Resetting the maintenance
service indicator ........................... 402
Vehicle care........................................ 403
Cleaning and care of the vehicle ... 403
Practical hints.................................. 413
What to do if … ................................... 414
Lamps in instrument cluster ......... 414
Lamp in center console ................ 425
Vehicle status messages in the
multifunction display .................... 427
Where will I find ...? ............................ 467
First aid kit.................................... 467
Vehicle tool kit.............................. 467
Spare wheel .................................. 471
Unlocking / locking in an emergency .. 474
Unlocking the vehicle ................... 474
Locking the vehicle ....................... 475
Fuel filler flap ................................ 475
Resetting activated head restraints.... 477
Vehicles without Rear Seat
Entertainment Package................. 477
Vehicles with Rear Seat
Entertainment Package*............... 478
Replacing SmartKey batteries ............ 479
Replacing bulbs .................................. 480
Bulbs............................................. 480
Replacing bulbs for front lamps .... 483
Replacing bulbs for rear lamps ..... 487

63 Getting started
Driving
The coolant temperature is above
248°F (120°C)
The coolant is too hot and is no longer
cooling the engine.
Stop the vehicle in a safe location as
soon as possible and turn off the
engine. Allow engine and coolant to
cool.
Check the coolant level and add
coolant if necessary (
page 360).In case of accident
If the vehicle is leaking fuel:
Do not start the engine under any
circumstances.
Notify local fire and/or police authori-
ties.
If the extent of the damage cannot be
determined:
Contact an authorized Mercedes-Benz
Light Truck Center or call Roadside
Assistance.
If no damage can be determined on the

major assemblies

fuel system

engine mount:
Start the engine in the usual manner.

161 Controls in detail
Control system
Menus, submenus and functions
Menu1Menu2Menu3Menu4Menu5
Standard displayAUDIONAV*AIRMATIC*/CompassDISTRONIC*
(page 164)(page 165)(page 167)(page 168)(page 262)
Commands/submenus
Trip- and main odometerSelecting radio stationRoute guidance
instructions, current
direction traveledAIRMATIC*Status and settings
Checking tire inflation
pressureSelecting satellite radio
station*Compass
Checking coolant
temperatureOperating CD player
Calling up digital
speedometer or outside
temperature
Calling up maintenance
service indicator
iThe headings used in the menus table are
designed to facilitate navigation within thesystem and are not necessarily identical to those
shown in the control system displays. The first function displayed in each menu will automati-
cally show you which part of the system you are
in.

164 Controls in detail
Control system
Standard display menu
In the standard display, the main odometer
and the trip odometer appear in the multi-
function display.
1Trip odometer
2Main odometer
If you see another display, press
buttonè orÿ repeatedly until
the standard display appears.
Press buttonkorj to select
the functions in the standard display
menu.The following functions are available:Checking coolant temperature
Press buttonk orj repeatedly
until the coolant temperature appears
in the multifunction display.
FunctionPage
Checking tire inflation pressure373
Checking coolant temperature164
Calling up digital speedometer or
outside temperature165
Calling up maintenance service
indicator402
Warning!G

Driving when your engine is 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 which can occur
just by opening the hood. Stay away
from the engine if you see or hear steam
coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of
the vehicle and do not stand near the vehicle
until the engine has cooled down.

165 Controls in detail
Control system
Calling up digital speedometer or
outside temperature
Press buttonk orj repeatedly
until the digital speedometer or the
outside temperature appears in the
multifunction display.
Digital speedometer
Outside temperature
AUDIO menu
The functions in the
AUDIO menu operate
the audio equipment which you currently
have turned on.
If no audio equipment is currently turned
on, the message
AUDIO off appears in the
multifunction display.
The following functions are available:!Excessive coolant temperature triggers
a warning message in the multifunction
display (
page 448).
The engine should not be operated with a
coolant temperature above 248°F (120°C).
Doing so may cause serious engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.
iDuring severe operating conditions, e.g.
stop-and-go city traffic, the coolant temperature
may rise close to 248°F (120°C).iYou can select whether the digital speed-
ometer or the outside temperature is to be
displayed.
You can change the setting in the submenu
Instrument Cluster via the function Status
Line Display
, see “Selecting display (digital
speedometer or outside temperature) for status
indicator” (
page 175).
FunctionPage
Selecting radio station166
Selecting satellite radio station*166
Operating CD player167

219 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.
In addition, the air conditioning dehumidi-
fies the interior air at outside temperatures
above 41°F (5° C) and helps prevent
window fogging.
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 button9 (page 210).
The indicator lamp on the button goes
out.
Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.
Press button9 (page 210) again.
The indicator lamp on the button
comes on.
The air conditioning uses the refrigerant
R134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.
Residual heat and ventilation
With the engine switched off, it is possible
to continue to heat or ventilate the interior
for up to 30 minutes. This feature makes
use of the residual heat produced by the
engine.
Activating
Switch off the ignition (page 39).
Press button9 (page 210).
The indicator lamp on the button
comes on.
iCondensation may drip out from underneath
the vehicle. This is normal and not an indication
of a malfunction.
Warning!G
If you turn off the cooling function, the inte-
rior air is not dried. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
!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.
iHow long the system will provide heating
depends on

the coolant temperature

the battery voltage
Regardless of the temperature and air volume
set on the climate control panel, an interior tem-
perature is aimed at by 72°F (22°C) and the
blower runs on low speed to protect the vehicle
battery.

220 Controls in detail
Climate control
Deactivating
Press button9 (page 210) again.
The indicator lamp on the button goes
out.
Rear climate control*
The control panel is located on the rear of
the front center console.
Rear climate control panel
Activating rear climate control
Press buttonU.
The indicator lamp on the button
comes on. The air volume and air distri-
bution are adjusted automatically.
iThe residual heat is automatically turned off:

when the ignition is switched on

after about 30 minutes

if the coolant temperature is too low

if the battery voltage drops
iThe rear climate control panel is only avail-
able if your vehicle is equipped with seat heating
for the second-row seats* or Rear Audio
feature* (see separate COMAND System operat-
ing instructions).
1Rear climate control on
(automatic mode)
2Air distribution (directs air through
the center air vents)
3Rear air conditioning off
4Air distribution (directs air through
the footwells and side air vents)
5Right rear center air vent, adjustable
6Left rear center air vent, adjustable
iThe climate control must be switched on
(
page 221).
iThe temperature is adjusted according to
the settings for the front passenger side made
on the front climate control panel (
page 213).

235 Controls in detail
3-zone automatic climate control*
Deactivating
Press button; (page 224) again.
The indicator lamp on the button goes
out.
Residual heat and ventilation
With the engine switched off, it is possible
to continue to heat or ventilate the interior
for up to 30 minutes. This feature makes
use of the residual heat produced by the
engine.Activating
Switch off the ignition (page 39).
Press button9 (page 224).
The indicator lamp on the button
comes on.
Deactivating
Press button9.
The indicator lamp on the button goes
out.
iIf you manually set the temperature, air
volume 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.
iHow long the system will provide heating
depends on

the coolant temperature

the battery voltage
Regardless of the temperature and air volume
set on the automatic climate control panel, an
interior temperature is aimed at by 72°F (22°C)
and the blower runs on low speed to protect the
vehicle battery.
iThe residual heat is automatically turned off:

when the ignition is switched on

after about 30 minutes

if the coolant temperature is too low

if the battery voltage drops

350 Operation
Driving instructions
Emission control
Certain engine systems serve to keep the
toxic components of the exhaust gases
within permissible legal limits.
These systems, of course, will function
properly only when maintained strictly
according to factory specifications.
Any adjustments on the engine should
therefore be carried out only by qualified
Mercedes-Benz Light Truck Center
authorized technicians.
Engine adjustments should not be altered
in any way. Moreover, the specified service
jobs must be carried out regularly accord-
ing to Mercedes-Benz servicing require-
ments. For details refer to the
Maintenance Booklet.Coolant temperature
During severe operating conditions and
stop-and-go city traffic, the coolant
temperature may rise to approximately
248°F (120°C).
The engine should not be operated
with the coolant temperature above
248°F (120°C). Doing so may cause seri-
ous engine damage which is not covered
by the Mercedes-Benz Limited Warranty.
Warning!G
Inhalation of exhaust gas is hazardous to
your health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause un-
consciousness and possible death.
Do not run the engine in confined areas
(such as a garage) which are not properly
ventilated. If you think that exhaust gas
fumes are entering the vehicle while driving,
have the cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one win-
dow fully open at all times.

354 Operation
At the gas station
Low outside temperatures
(diesel engine)
To prevent malfunctions, diesel fuel with
improved cold flow characteristics is of-
fered in the winter months. Check with
your fuel retailer.Check regularly and before a long trip
Open the hood (page 356).
Example illustration R 350 4MATIC
1Coolant level
2Brake fluid
3Windshield washer system and
headlamp cleaning system*
iDiesel engine:
If you have driven the vehicle until the tank was
empty, the fuel system needs to be bled
(
page 502).
!Diesel engine:
The engine is more susceptible to wear and
damage if you use

marine diesel fuel

heating oil

additives
The exhaust aftertreatment device will be
seriously damaged if you use

LOW SULFUR HIGHWAY DIESEL FUEL
(500 ppm SULFUR MAXIMUM)

any other diesel fuel with a sulfur content of
above 15 ppm
The use of such non-approved fuels and/or
special additives is not covered by the
Mercedes-Benz Limited Warranty.
!Do not fill the tank with gasoline. Do not
blend diesel fuel with gasoline or kerosine. The
fuel system and engine will otherwise be dam-
aged, which is not covered by the
Mercedes-Benz Limited Warranty.