2008 MERCEDES-BENZ R320 warning light

449 Practical hints
What to do if …
During severe operation conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
Observe the coolant temperature in the
multifunction display (
page 164).
If the temperature rises again:
Contact an authorized
Mercedes-Benz Light Truck Center
immediately.
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 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 the
engine has cooled down.
!The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious damage which is
not covered by the Mercedes-Benz Limited
Warranty.

450 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 360).
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.

451 Practical hints
What to do if …
When the message Check engine oil
level at next refueling.
appears while
the engine is running and at operating tem-
perature, the engine oil level has dropped
to approximately the minimum level.
When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.Visually check for oil leaks. If no obvious oil
leaks are noted, drive to the nearest
service station where the engine oil should
be topped to the required level with an
approved engine oil.
For information on approved engine oils,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Light Truck
Center.
Display symbolDisplay messagePossible cause/consequencePossible solution
NCheck engine oil level
at next refueling.The engine oil level is too low.Check the engine oil level (page 358).
!The engine oil level warning should not be
ignored. Extended driving with the symbol
displayed could result in serious engine damage
that is not covered by the Mercedes-Benz
Limited Warranty.

471 Practical hints
Where will I find ...?
Setting up the collapsible wheel chock
The collapsible wheel chock serves to ad-
ditionally secure the vehicle, e.g. while
changing the wheel.
1Tilt the plate upward
2Fold the lower plate outward
3Insert the plateTilt both plates upward1.
Fold the lower plate outward2.
Guide the tabs of the lower plate all the
way into the openings of base plate3.
For information on where to place wheel
chocks when changing a wheel, see
“Lifting the vehicle” (
page 493).
Spare wheel
Warning!G
The dimensions of the spare wheel are
different from those of the road wheels. As
a result, the vehicle handling characteristics
change when driving with a spare wheel
mounted. Adapt your driving style accord-
ingly.
The spare wheel is for temporary use only.
When driving with a spare wheel mounted,
ensure proper tire inflation pressure and do
not exceed a vehicle speed of
50 mph (80 km/ h).
Drive to the nearest Mercedes-Benz Light
Truck Center as soon as possible to have the
spare wheel replaced with a regular road
wheel.
Never operate the vehicle with more than
one spare wheel mounted.
Do not switch off the ESP
® with a spare
wheel mounted.

477 Practical hints
Resetting activated head restraints
Resetting activated head restraints
If the active head restraints have been
triggered in a rear-end collision, the active
head restraints must be reset. Otherwise,
the active head restraints cannot offer
any additional protection in the event of
another rear-end collision.
You can tell that the active head restraints
have been activated when they have been
moved forward and cannot be adjusted.
Vehicles without Rear Seat Entertain-
ment Package*1Pull
2Adjust downward
3Press
Pull the top of the head restraint cush-
ion in direction of arrow 1 as far as it
will go.
Adjust the head restraint cushion
downward in direction of arrow 2 as
far as it will go.
Firmly press the top of the active head
restraint cushion towards the head
restraint cover in direction of arrow 3
until it engages.
Warning!G
For safety reasons, have the active head
restraints checked by an authorized
Mercedes-Benz Light Truck Center after a
rear-end collision.
Warning!G
When pushing back the head restraint
cushion, take care that your fingers do not
become caught between the head restraint
cushion and the cover. Failing to do so may
lead to injury.
!Be careful not to damage upholstery.
iFor your convenience, we recommend that
you have this work carried out by an authorized
Mercedes-Benz Light Truck Center.
iPressing the head restraint cushion back
requires high force. If you encounter difficulties
when pushing the head restraint back, please
have the procedure performed at an authorized
Mercedes-Benz Light Truck Center.


479 Practical hints
Replacing SmartKey batteries
Replacing SmartKey batteries
If the batteries in the SmartKey or the
SmartKey with KEYLESS-GO* are
discharged, the vehicle can no longer be
locked or unlocked. It is recommended to
have the batteries replaced at an autho-
rized Mercedes-Benz Light Truck Center.
Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key from the
SmartKey (
page 474).
1Mechanical key
2Battery compartment
Insert mechanical key 1 into opening.
Press mechanical key 1 in direction of
arrow.
The battery compartment is unlatched.
Pull battery compartment 2 out of the
SmartKey housing.
3Batteries
4Contact springs
Pull out batteries3.
Using a line-free cloth, insert new bat-
teries 3 under contact springs 4 with
the positive terminal (+) side facing up.
Return battery compartment 2 into
housing until it locks into place.
Slide mechanical key 1 back into
SmartKey.
Check the operation of the SmartKey
or SmartKey with KEYLESS-GO*.
Warning!G
Keep the batteries out of reach of children.
If a battery is swallowed, seek medical help
immediately.
iWhen inserting batteries, make sure they
are clean and free of lint.
iWhen replacing batteries, always replace
both batteries. The required replacement
batteries are available at any Mercedes-Benz
Light Truck Center.

482 Practical hints
Replacing bulbs
Notes on bulb replacement

Only use 12-volt bulbs of the same type
and with the specified watt rating.

Switch the lights off before changing a
bulb to prevent short circuits.

Always use a clean lint-free cloth when
handling bulbs.

Your hands should be dry and free of oil
and grease.

If the newly installed bulb does not
come on, contact an authorized
Mercedes-Benz Light Truck Center.Have the LEDs and bulbs for the following
lamps replaced by an authorized
Mercedes-Benz Light Truck Center:

the additional turn signal lamps in the
exterior rear view mirrors

the high mounted brake lamp

the Bi-Xenon* low beam lamps

the Bi-Xenon* high beam flasher spot-
light

the front side marker lamps
Warning!G
Bulbs and bulb sockets can be very hot.
Allow the lamp to cool down before chang-
ing a bulb.
Keep bulbs out of reach of children.
Halogen lamps contain pressurized gas.
A bulb can explode if you:

touch or move it when hot

drop the bulb

scratch the bulb
Wear eye and hand protection.
Because of high voltage in Xenon lamps, it is
dangerous to replace the bulb or repair the
lamp and its components. We recommend
that you have such work done by a qualified
technician.!Do not replace the bulbs yourself. You could
otherwise damage the LEDs or parts of the
vehicle. Only have the LEDs replaced by an
authorized Mercedes-Benz Light Truck Center.

489 Practical hints
Replacing wiper blades
Replacing wiper blades
Front wiper blades
Remove the SmartKey from the starter
switch.
Vehicles with KEYLESS-GO*:
Make sure the vehicle’s on-board
electronics have status0
(
page 41).Removing
Fold the wiper arms forward until they
engage.
1Wiper blade
2Tab
3Wiper arm
Press tabs2 together.
Tilt wiper blade 1 away from wiper
arm 3.
Take off wiper blade 1 in direction of
arrow.
Warning!G
For safety reasons, switch off wipers and
remove SmartKey from starter switch
(vehicles with KEYLESS-GO*: Make sure
the vehicle’s on-board electronics have
status0) before replacing a wiper blade.
Otherwise the motor could suddenly turn on
and cause injury.
Warning!G
Wiper blades are components that are
subject to wear and tear. Replace the wiper
blades twice a year, preferably in the spring
and fall. Otherwise the windows will not be
properly wiped. As a result, you may not
be able to observe surrounding traffic condi-
tions and could cause an accident.
!Never open the hood when the wiper arms
are folded forward.
Hold on to the wiper when folding the wiper arm
back. If released, the force of the impact from
the tensioning spring could crack the windshield.
Do not allow the wiper arms to contact the wind-
shield glass without a wiper blade inserted.
For your convenience, we recommend that you
have this work carried out by an authorized
Mercedes-Benz Light Truck Center.!Do not pull on the wiper blade inserts. They
could tear.