2008 MERCEDES-BENZ R320 octane

13 Introduction
Operator’s Manual
Change of address or ownership
If you change your address, be sure to
send in the “Change of Address Notice”
found in the Service and Warranty Informa-
tion Booklet, or simply call the
Mercedes-Benz Customer Assistance
Center (in the USA) at
1-800-FOR-MERCedes, or Customer
Service (in Canada) at 1-800-387-0100. It
is in your own interest that we can contact
you should the need arise.
If you sell your Mercedes, please leave all
literature with the vehicle to make it avail-
able to the next operator.
If you bought this vehicle used, be sure to
send in the “Notice of Purchase of Used
Truck” found in the Service and Warranty
Information Booklet, or call the
Mercedes-Benz Customer Assistance
Center (in the USA) at
1-800-FOR-MERCedes, or Customer
Service (in Canada) at 1-800-387-0100.Operating your vehicle outside the USA
or Canada
If you plan to operate your vehicle in for-
eign countries, please be aware that:

service facilities or replacement parts
may not be readily available,

unleaded gasoline for vehicles with
catalytic converters may not be avail-
able; the use of leaded fuels will
damage the catalysts,

gasoline may have a considerably
lower octane rating, and improper fuel
can cause engine damage.

353 Operation
At the gas station
Briefly push on fuel filler flap at the
position indicated the arrow.
The fuel filler flap opens slightly.
Open the fuel filler flap completely.
Turn the fuel cap to the counterclock-
wise and hold on to it until possible
pressure is released.
Take off the fuel cap.
To prevent fuel vapors from escaping
into open air, fully insert filler nozzle
unit.
Only fill your tank until the filler nozzle
unit cuts out – do not top off or overfill.
Replace the fuel cap by turning it clock-
wise until it audibly engages.
Close the fuel filler flap.
You should hear the latch close shut.
!The fuel filler cap is tethered to the fuel filler
neck. Do not drop the cap. It could damage the
vehicle paint finish.
Warning!G
Overfilling of the fuel tank may create pres-
sure in the system which could cause a gas
discharge. This could cause the gas to spray
back out when removing the fuel pump
nozzle, which could cause personal injury.
iLeaving the engine running and the fuel cap
open can cause the yellow fuel tank reserve
warning lamp to flash and the? malfunction
indicator lamp (USA only) or the± malfunc-
tion indicator lamp (Canada only) comes on.
For more information, see “Practical hints”
(
page 418).
iGasoline engine:
Only use premium unleaded gasoline with a min-
imum Posted Octane Rating of 91 (average of
96 RON/86 MON). Information on gasoline
quality can normally be found on the fuel pump.
Please contact gas station personnel in case
labels on the pump cannot be found.
For more information on gasoline, see “Premium
unleaded gasoline (gasoline engine)”
(
page 539), see “Fuel requirements”
(
page 540), and the Factory Approved Service
Products pamphlet (USA only) or contact an
authorized Mercedes-Benz Light Truck Center.
iDiesel engine:
Only use commercially available vehicular
ULTRA-LOW SULFUR HIGHWAY DIESEL FUEL
(15 ppm SULFUR MAXIMUM). Information on
diesel quality can normally be found on the fuel
pump. Please contact gas station personnel in
case labels on the pump cannot be found.
For more information on diesel fuels, refer to the
Factory Approved Service Products pamphlet
(USA only) or contact an authorized
Mercedes-Benz Light Truck Center.


527 Technical data
Engine
Engine
ModelR 320 CDI 4MATIC (251.122)1R 350 (251.156)1,2
R 350 4MATIC (251.165)1
1The quoted data apply only to the standard vehicle. See an authorized Mercedes-Benz Light Truck Center for the corresponding data of all special bodies and special
equipment.
2USA only.
Engine642272
Mode of operationDiesel 4-stroke engine4-stroke engine, gasoline injection
No. of cylinders66
Bore3.27 in (83.00 mm)3.66 in (92.90 mm)
Stroke3.62 in (92.00 mm)3.39 in (86.00 mm)
Total piston displacement182 cu in (2 987 cm3)213 cu in (3 498 cm3)
Compression ratio17.7:110.7:1
Output acc. to SAE J 1349215 hp/4 000 rpm
(160 kW/4 000 rpm)268 hp/6 000 rpm3
(200 kW/6 000 rpm)
3Premium fuel required. Performance may vary with fuel octane rating.
Maximum torque acc. to SAE J 1349400 lb-ft/1 600 - 2 400 rpm
(543 Nm/1 600 - 2 400 rpm)258 lb-ft/2 400 - 5 000 rpm
(350 Nm/2 400 - 5 000 rpm)
Maximum engine speed4 500 rpm6500 rpm
Firing order1-4-2-5-3-61-4-3-6-2-5
Poly-V-belt2 035 mm2404 mm

528 Technical data
Engine
ModelR 550 4MATIC (251.172)1,2
1The quoted data apply only to the standard vehicle. See an authorized Mercedes-Benz Light Truck Center for
the corresponding data of all special bodies and special equipment.
2Canada only.
Engine273
Mode of operation4-stroke engine, gasoline injection
No. of cylinders8
Bore3.86 in (98.00 mm)
Stroke3.56 in (90.50 mm)
Total piston displacement333cuin (5461cm3)
Compression ratio10.7:1
Output acc. to SAE J 1349382 hp/6 000 rpm3
(285 kW/6 000 rpm)
3Premium fuel required. Performance may vary with fuel octane rating.
Maximum torque acc. to SAE J 1349391 lb-ft/2 800 - 4 800 rpm
(530 Nm/2 800 - 4 800 rpm)
Maximum engine speed6 500 rpm
Firing order1-5-4-2-6-3-7-8
Poly-V-belt2 404 mm

537 Technical data
Fuels, coolants, lubricants, etc.
ModelCapacityFuels, coolants, lubricants, etc.
Power steeringapprox. 1.3 US qt (1.2 l)MB Power Steering Fluid or approved
Dexron III ATF
Front wheel hubsapprox. 1.5 oz (43 g) eachHigh temperature roller bearing grease
Brake systemMB Brake Fluid (DOT 4+)
Cooling systemR 320 CDI 4MATIC10.0 US qt (9.5 l)MB Anticorrosion/Antifreeze
R 3501, R 350 4MATIC
1USA only.
10.0 US qt (9.5 l)
R 550 4MATIC2
2Canada only.
12.7 US qt (12 l)
Fuel tank
including a reserve of21.1 US gal (80.0 l)
approx. 3.4 US gal (13.0 l)Gasoline engine:
Premium unleaded gasoline:
Minimum Posted Octane 91
(Avg.of96RON/86MON)
Diesel engine:
ULTRA-LOW SULFUR HIGHWAY DIESEL
FUEL (15 ppm SULFUR MAXIMUM)

539 Technical data
Fuels, coolants, lubricants, etc.
Brake fluid
Only brake fluid approved by
Mercedes-Benz is recommended. Your
authorized Mercedes-Benz Light Truck
Center will provide you with additional
information.Premium unleaded gasoline
(gasoline engine)
Warning!G
During vehicle operation, the boiling point of
the brake fluid is continuously reduced
through the absorption of moisture from the
atmosphere. Under extremely strenuous
operating conditions, this moisture content
can lead to the formation of bubbles in the
system, thus reducing the system’s
efficiency.
Therefore, the brake fluid must be
replaced regularly. Refer to your vehicle’s
Maintenance Booklet for replacement
interval.
Warning!G
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious
personal injury.
Never allow sparks, flame or smoking mate-
rials near gasoline!
Turn off the engine before refueling.
Whenever you are around gasoline, avoid in-
haling fumes and skin or clothing contact,
extinguish all smoking materials.
Direct skin contact with gasoline and the in-
halation of gasoline vapors are damaging to
your health.
!To maintain the engine’s durability and
performance, premium unleaded gasoline must
be used. If premium unleaded gasoline is not
available and low octane fuel is used, follow
these precautions:

Have the fuel tank only partially filled with
unleaded regular gasoline and fill up with
premium unleaded gasoline as soon as
possible.

Avoid full throttle driving and abrupt acceler-
ation.

Do not exceed an engine speed of 3 000 rpm
if the vehicle is loaded with a light load such
as two persons and no luggage.

Do not exceed2/3of maximum accelerator
pedal position if the vehicle is fully loaded or
operating in mountainous terrain.

540 Technical data
Fuels, coolants, lubricants, etc.
Fuel requirements
Gasoline engine
Only use premium unleaded fuel.

The octane number (posted at the
pump) must be 91 min. It is an
average of both the Research Octane
Number (RON) and the Motor Octane
Number (MON): (RON+MON) /2.
This is also known as the ANTI-KNOCK
INDEX.
Unleaded gasoline containing oxygenates
such as ethanol, IPA, IBA and TBA can be
used provided the ratio of any one of these
oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is
not allowed. Gasohol, which contains
10% ethanol and 90% unleaded gasoline,
can be used.These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc.
Diesel engine
Only use commercially available vehicular
ULTRA-LOW SULFUR HIGHWAY DIESEL
FUEL (15 ppm SULFUR MAXIMUM).
To prevent malfunctions, diesel fuel with
improved cold flow characteristics is
offered in the winter months. Check with
your fuel retailer.
Gasoline additives (gasoline engine)
A major concern among engine
manufacturers is carbon build-up caused
by gasoline. Mercedes-Benz recommends
only the use of quality gasoline containing
additives that prevent the build-up of
carbon deposits.
After an extended period of using fuels
without such additives carbon deposits
can build up, especially on the intake
valves and in the combustion area, leading
to engine performance problems such as:

Warm-up hesitation

Unstable idle

Knocking/pinging

Misfire

Power loss
!Do not fill the tank with gasoline. Do not
blend diesel fuel with gasoline or kerosine.
The fuel system and engine will otherwise be
damaged, which is not covered by the
Mercedes-Benz Limited Warranty.

552 Index
Fuel 352, 537, 539
Additives 540
Capacities, Fuel tank 537
Consumption statistics 185
Filling the tank 352
Fuel filler flap and cap 352
Fuel gauge 29
Fuel reserve warning lamp 29, 424
Premium unleaded
gasoline 352, 539, 540
Requirements, Octane rating 540
Fuel cap
Messages in the multifunction
display 452
Fuel filler flap 352
Locking/unlocking 352
Opening 352
Opening in an emergency 475
Fuels, coolants, lubricants etc. 536Fuses 518
Fuse box, Cargo compartment 519
Fuse box, Engine compartment 519
Fuse box, Passenger
compartment 520
Fuse chart 467, 518
Fuse extractor 467, 518
Replacing 518
Spare fuses 467, 518
G
Garage door opener 329
Gasoline see Fuel
GAWR 394
Gear range
Automatic transmission 199
Limiting 199
Shifting into optimal 202Gear selector lever 25, 53, 190
Gearshift pattern 53, 190
Message in the display 437
Messages in the multifunction
display 437
Position 193
Shifting procedure 193
Transmission position 194
Global locking/unlocking see
Key, SmartKey
Glove box 304
Good visibility 203
Gross Axle Weight Rating see GAWR
Gross Trailer Weight see GTW
Gross Vehicle Weight Rating see GVWR
Gross Vehicle Weight see GVW
GTW 394
GVW 394
GVWR 394