2010 MERCEDES-BENZ R320 tow

Example illustration: Tire inflation pressures for all
approved, factory equipped tires
Some tire inflation pressure labels may only
show the rim diameter instead of the entire
tire size, e.g. R 18 or 18".
The rim diameter is part of the tire size as
specified on the tire sidewall (Y page 245).
Example illustration: Tire inflation pressures
specific to rim diameter
i
When towing a trailer, inflate the tires to
the tire inflation pressure as specified for a
fully loaded vehicle.
Potential problems associated with
underinflated and overinflated tires Underinflated tires
G
Warning!
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated. Underinflated tires can
R
cause excessive and uneven tire wear
R adversely affect fuel economy
R lead to tire failure from being overheated
R adversely affect handling characteristics
Overinflated tires G
Warning!
Follow recommended tire inflation pressures.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Overinflated tires can
R adversely affect handling characteristics
R cause uneven tire wear
R be more prone to damage from road
hazards
R adversely affect ride comfort
R increase stopping distance Checking tire inflation pressure
Safety notes G
Warning!
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc. 230
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X
Step 5: Determine the combined weight of
luggage and cargo being loaded on the
vehicle. That weight may not safely exceed
the available cargo and luggage load
capacity calculated in step 4.
X Step 6 (if applicable): If your vehicle will
be towing a trailer, load from your trailer
will be transferred to your vehicle. Consult
this

manual to determine how this reduces
the available cargo and luggage load
capacity of your vehicle ( Y page 240).
The following table shows examples on how
to calculate total and cargo load capacities
with varying seating configurations and
number and size of occupants. The following
examples use a load limit of 1 500 lbs. This
is

for illustration purposes only. Make sure
you are using the actual load limit for your
vehicle stated on the vehicle’s Tire and
Loading Information placard ( Y page 237).238
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Weight Rating (GVWR) and the Gross Axle
Weight Rating (GAWR) for either the front or
rear axle. You can obtain the GVWR and
GAWR from the certification label. The
certification label can be found on the driver’s
door B-pillar, see the “Technical data” section
(Y page 344).
Gross Vehicle Weight Rating (GVWR): The
total weight of the vehicle, all occupants, all
cargo, and the trailer tongue load (if
applicable) must never exceed the GVWR.
Gross Axle Weight Rating (GAWR): The total
allowable weight that can be carried by a
single axle (front or rear).
To assure that your vehicle does not exceed
the maximum permissible weight limits
(GVWR and GAWR for front and rear axle),
have the loaded vehicle (including driver,
passengers and all cargo and, if applicable,
trailer fully loaded) weighed on a suitable
commercial scale.
Trailer tongue load
The tongue load of any trailer is an important
weight to measure because it affects the load
you can carry in your vehicle. If a trailer is
towed, the tongue load must be added to the
weight of all occupants riding and any cargo
you are carrying in the vehicle. The tongue
load typically is between 10% and 15% of the
trailer weight and everything loaded in it.
Maximum tire load
G
Warning!
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver’s door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure. i
For illustration purposes only. Actual data
on tires are specific to each vehicle and
may vary from data shown in above
illustration.
The maximum tire load rating : is the
maximum weight the tires are designed to
support.
For more information on tire load rating, see
(Y page 245).
For information on calculating total and cargo
load capacities, see ( Y page 237). Direction of rotation
Unidirectional tires offer added advantages,
such as better hydroplaning performance. To
benefit, however, you must make sure the
tires rotate in the direction specified.
An arrow on the sidewall indicates the
intended direction of rotation of the tire.
Spare wheels may be mounted against the
direction of rotation (spinning) even with a
unidirectional tire for temporary use only until
the regular drive wheel has been repaired or
replaced. Always observe and follow
applicable temporary use restrictions and
speed limitations indicated on the spare
wheel. MOExtended system
The MOExtended system allows you to
continue driving your vehicle even if there is
a total loss of pressure in one or more tires. 240
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X
Reduce vehicle speed.
X Avoid track grooves in the road.
X Apply brakes cautiously. Standing water
! Do not drive through flooded areas.
Before
driving through water, determine its
depth.
If you must drive through standing water,
drive slowly to prevent water from entering
the passenger compartment or the engine
compartment. Water in these areas could
cause damage to electrical components or
wiring of the engine or transmission, or
could result in water being ingested by the
engine through the air intake causing
severe internal engine damage. Any such
damage is not covered by the Mercedes-
Benz Limited Warranty.
Prevent water from entering the passenger
compartment or the engine compartment. If
you must drive through standing water, keep
in mind that
R the maximum depth of the water may not
exceed 10 in (25 cm)
R you must drive slowly
i Vehicles with AIRMATIC:
If you have selected the raised level
(Y page 155) before driving through
standing water, the maximum water depth
is 12 in (30 cm). Trailer towing
G
Warning!
Failure to use proper equipment and driving
technique can result in a loss of vehicle
control when towing a trailer.
Improper towing or failure to follow the
instructions in this manual can result in
vehicle damage and/or serious personal injury. Follow the guidelines below carefully
to assure safe trailer operation.
Contact

an authorized Mercedes-Benz Center
should you require an explanation of
information contained in this manual.
Trailer hitch R
Only
install a trailer hitch receiver approved
for your vehicle.
For information on availability and
installation, contact an authorized
Mercedes-Benz Center.
R The bumpers on your vehicle are not
designed for use with clamp-type hitches.
Do not attach rental hitches or other
bumper-type hitches to them.
R To reduce the possibility of damage,
remove the hitch ball adapter from the
receiver when not in use.
Electrical connections The vehicle is prewired to accept the seven-
wire harness included in the Mercedes-Benz
approved trailer hitch receiver kit.
i
A four-pole conversion plug is available
from your authorized Mercedes-Benz
Center as a spare part.
For further information, contact an
authorized Mercedes-Benz Center.
Vehicle

and trailer weights and ratings The Gross Trailer Weight (GTW) is the weight
of the trailer plus the weight of all cargo,
equipment, luggage, etc. loaded on the
trailer. The maximum permissible GTW to be
towed: 3
500 lb (1 588 kg).
Trailer Tongue Weight Rating (TWR) is the
maximum permissible weight on the trailer
tongue: 350 lb (158 kg) limit for Mercedes-
Benz approved hitch receiver. 256
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Loading a trailer
R
When
loading a trailer, you should observe
that neither the permissible GTW, nor the
Gross Vehicle Weight Rating (GVWR) are
exceeded. The GVWR is indicated on the
certification label located on the driver’s
door B-pillar ( Y page 236).
Maximum permissible values are listed on
the safety compliance certification labels
for the vehicle and for the trailer to be
towed.
The lowest value listed must be selected
when determining how the vehicle and
trailer are loaded.
R The tongue weight at the hitch ball must be
added to the rear axle weight to prevent
exceeding the rear Gross Axle Weight
Rating (GAWR). The GAWR is indicated on
the certification label located on the
driver’s door B-pillar ( Y page 236).
i Mercedes-Benz recommends loading the
trailer in such a manner that it has a tongue
weight between 8 % and 10 % of the GTW.
i The weight of other accessories,
passengers and cargo will reduce the
maximum trailer weight and tongue weight
your vehicle can tow.
Checking weights of vehicle and trailer
R To assure that the towing vehicle and trailer
are in compliance with the maximum
permissible weight limits, have the loaded
rig (towing vehicle including driver,
passengers and cargo, trailer fully loaded)
weighed on a commercial scale.
R Check the vehicle’s front and rear gross
axle weight, the Gross Trailer Weight (GTW)
and tongue weight.
The values as measured must not exceed
the weight limits listed under “Vehicle and
trailer weights and ratings” ( Y page 256).Coupling a trailer G
Warning!
Vehicles with AIRMATIC: While you are
coupling or decoupling a trailer, make sure
nobody locks or unlocks the vehicle and/or
opens or closes doors or the tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
switch or the vehicle level control system
when coupling/decoupling the trailer.
Observe maximum permitted trailer
dimensions (width and length).
Most states and all Canadian provinces
require
R safety chains between the towing vehicle
and the trailer
The chains should be criss-crossed under
the trailer tongue. They must be attached
to the hitch receiver, and not to the
vehicle’s bumper or axle.
Make sure to leave enough slack in the
chains to permit turning corners.
R a separate brake system at various trailer
weights
R a break-away switch on trailers with a
separate brake system.
Check

with your local state laws for specific
requirements.
The switch activates the trailer brakes in
the possible event that the trailer might
separate from the tow vehicle.
! Do not connect a trailer brake system (if
trailer is so equipped) directly to the
vehicle’s hydraulic brake system, as your
vehicle is equipped with antilock brakes. If
you do, neither the vehicle’s brakes nor the
trailer’s brakes will function properly.
i The provided vehicle electrical wiring
harness for trailer towing has a brake signal
wire for hook-up to a brake controller. Driving instructions
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X
Make sure the automatic transmission is in
park position P (Y page 116).
X Engage the parking brake for the vehicle
(Y page 114).
X Start the engine (Y page 110).
X Vehicles with AIRMATIC:
Set the vehicle level to highway
(Y page 154) and set the ADS to AUTO or
COMF (Y page 153).
X Turn off the engine ( Y page 114).
X Close all doors and the tailgate.
X Attach the trailer.
X Plug in all electrical connectors.
i Vehicles with AIRMATIC:
When you are towing a trailer, the vehicle
level
always remains in the highway setting.
The following applies additionally when
towing a trailer:
R The vehicle is lowered to the highway
level when it reaches a speed of 5 mph
(8 km/h) if not set to highway level.
R The highspeed level is not available.
The restrictions that apply to towing also
apply when using accessories that are
connected to the trailer power socket, such
as a bicycle rack.
Towing a trailer There are many different laws, including
speed limit restrictions, having to do with
trailer

towing. Make sure your rig will be legal,
not only for where you reside, but also for
where you will be driving. A good source for
this information can be the police or local
authorities.
Note the following, when driving with a trailer:
R In order to gain skill and an understanding
of the vehicle’s behavior, you should practice turning, stopping and backing up
in an area which is free of traffic.
R Before you start driving check the
-trailer hitch
- break-away switch
- safety chains
- electrical connections
- lighting
- tires
R Adjust the mirrors

(Y page 94) to permit
unobstructed view beyond rear of trailer.
R If the trailer has electric brakes, start your
vehicle and trailer moving slowly, and then
apply only the trailer brake controller by
hand to make sure the brakes are working
properly.
R Always secure items in the trailer to
prevent load shifts while driving.
R When towing a trailer, check occasionally
to make sure the load is secure, and that
trailer lighting and brakes (if so equipped)
are functioning properly.
R Take into consideration that when towing a
trailer, the handling characteristics are
different and less stable from those when
operating the vehicle without a trailer.
It is important to avoid sudden maneuvers.
R The vehicle and trailer combination is
heavier, and therefore limited in
acceleration and climbing ability, and has a
larger braking distance.
It is more prone to reacting to cross wind
gusts, and requires more sensitive steering
input.
R If possible, do not brake abruptly, but
rather engage the brake slightly at first to
permit the trailer to activate its brake. Then
increase the braking force.
! If the trailer should begin to sway, reduce
the vehicle’s speed immediately. 258
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Do not attempt to straighten out the tow
vehicle
and trailer by increasing the speed.
R If the transmission shifts between gears on
inclines repeatedly, shift to a lower gear
range manually ( Y page 119). Select 4, 3,
2 or 1.
A lower gear and reduction of speed
reduces the chance of engine overloading
and/or overheating.
R When going down an incline, shift into a
lower gear and use the engine’s braking
effect.
Avoid riding the brakes, thus overheating
the vehicle and trailer brakes (if so
equipped).
R If the engine coolant rises to an extremely
high temperature when the air conditioning
is on, turn off the air conditioning system.
Engine coolant heat can be additionally
vented by opening the windows, switching
the climate control fan speed to high and
setting the temperature control to the
maximum.
R During a passing maneuver extreme care
must be exercised since your vehicle with
a trailer will require additional passing
distance ahead than when driving without
a trailer.
Because your vehicle and trailer is longer
than your vehicle alone, you will also need
to go much farther ahead of the passed
vehicle before you can return to your lane.
Decoupling a trailer G
Warning!
Vehicles with AIRMATIC: While you are
coupling or decoupling a trailer, make sure
nobody locks or unlocks the vehicle and/or
opens or closes doors or the tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result. Make sure that you do not operate the ADS
switch or the vehicle level control system
when coupling/decoupling the trailer.
X Make sure the automatic transmission is in
park position P (Y page 116).
X Engage the parking brake for the vehicle
(Y page 114).
X Start the engine (Y page 110).
X Close all doors and the tailgate.
X Engage the parking brake for the trailer. G
Warning!
Vehicles with AIRMATIC: As soon as you
disconnect
the electrical connection between
the trailer and the vehicle, the vehicle will
lower. To help avoid personal injury, make
sure no one is near the wheel housing or
underneath the vehicle before the electrical
connection is disconnected.
When you decouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not press
the switches for vehicle level control or the
ADS.
X Disconnect all electrical plug connectors.
X Decouple the trailer.
X Make sure that the trailer coupling is free
of load.
X Turn off the engine ( Y page 114). Driving abroad
If
you plan to drive the vehicle outside the U.S.
or Canada, you should request dealer
network information for your destination from
any authorized Mercedes-Benz Center. Driving instructions
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Paintwork, painted body components
!
Affixing stickers, magnets, adhesive tape
or similar materials to painted body
components may damage the paintwork.
Mercedes-Benz approved Paint Care should
be applied when water drops on the paint
surface do not “bead up”. This should
normally be done every 3 to 5 months,
depending on the climate and washing
detergent used.
Mercedes-Benz approved Paint Cleaner
should be applied if the paint surface shows
signs of embedded dirt (i.e. loss of gloss).
Do not apply any of these products or wax if
your
vehicle is parked in the sun or if the hood
is still hot.
X Use the appropriate MB-Touch-Up Stick for
quick

and provisional repairs of minor paint
damage (i.e. chips from stones, vehicle
doors, etc.).
Engine cleaning Prior to cleaning the engine compartment,
make sure to protect electrical components
and connectors from contact with water and
cleaning agents.
Corrosion protection, such as MB
Anticorrosion Wax should be applied to the
engine compartment after every engine
cleaning. Before applying, all control linkage
bushings

and joints should be lubricated. The
poly-V-belt and all pulleys should be
protected from any wax.
Vehicle washing In the winter, thoroughly remove all traces of
road salt as soon as possible.
When

washing the vehicle underbody, do not
forget to clean the inner sides of the wheels.
i Vehicles with KEYLESS-GO:
If a door handle is hit by a strong jet of
water, and a SmartKey is within approximately 3 ft (1 m) of the vehicle, it
could

be inadvertently locked or unlocked.
Hand-wash
X Do not use hot water or wash your vehicle
in direct sunlight.
X Only use a soft, wet cloth or sponge to
clean the vehicle.
X Only use a mild vehicle wash detergent,
such as Mercedes-Benz approved Car
Shampoo.
X Thoroughly spray the vehicle with a
diffused jet of water.
X Do not spray directly towards the
ventilation intake.
X Use plenty of water and rinse the sponge
and chamois frequently.
X Rinse with clean water and dry with a
chamois thoroughly.
Do not allow cleaning agents to dry on the
finish.
Automatic car wash
You can have your vehicle washed in an
automatic

car wash from the start. Brushless
car washes are preferable.
X To protect the filter system, activate the air
recirculation mode using button d on
the climate control panel.
! Do
not clean your vehicle in an automatic
touchless car wash which uses caustic
spray. Caustic spray will damage the paint
or ornamental moldings.
If the vehicle is very dirty, prewash it before
running it through the automatic car wash.
! Make sure the combination switch is set
to wiper setting $. Otherwise, the rain
sensor could activate and cause the wipers
to move unintentionally. This may lead to
vehicle damage.
Due to the width of the vehicle, fold in
exterior rear view mirrors prior to running
the vehicle through an automatic car wash
to prevent damage to the mirrors. 264
Vehicle care
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