Page 323 of 539
322 OperationDriving instructionsCoolant temperature
During severe operating conditions,
e.g. stop-and-go traffic, the coolant tem-
perature may rise close to approximately
248°F (120°C).
The engine should not be operated with
the coolant temperature over 248°F
(120°C). Doing so may cause serious en-
gine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Warning!
G
Driving when your engine is badly over-
heated can cause some fluids, which
may have leaked into the engine com-
partment to catch fire. You could be se-
riously 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.
Page 325 of 539

324 OperationAt the gas station
Replace the fuel cap by turning it
clockwise until it audibly engages.
Close the fuel filler flap.
Check regularly and before a long trip
Open the hood (
page 326).
Example ML 5001Brake fluid
2Coolant level
3Windshield washer system and
headlamp cleaning system*
Engine oil level
For more information on engine oil, see
“Engine oil” (
page 327).Brake fluid
Coolant
For normal replenishing, use water (pota-
ble water quality).
For more information, see “Coolant level”
(
page 332) and see “Fuels, coolants, lu-
bricants, etc.” (
page 493).
iOnly use premium unleaded gasoline
with a minimum Posted Octane Rating
of 91 (average of 96 RON/86 MON).
Information on gasoline quality can
normally be found on the fuel pump.
For more information on gasoline, see
the Factory Approved Service Products
pamphlet.iLeaving the engine running and the fuel
cap open can cause the yellow engine
malfunction indicator lamp
?(USA only), ±(Canada only)
to illuminate.
For more information, see “Practical
hints” (
page 385).
!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks immediately. Noti-
fy an authorized Mercedes-Benz Light
Truck Center immediately. Do not add
brake fluid as this will not solve the
problem. For more information, see
“Practical hints” (
page 381).
Page 328 of 539

327 Operation
Engine compartment
Closing
Let the hood drop from a height of
approximately 1ft (30cm).
The hood will lock audibly.
Check to make sure the hood is fully
closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
Engine oil
The amount of oil your engine needs will
depend on a number of factors, including
driving style. Higher oil consumption can
occur when
the vehicle is new
the vehicle is driven frequently at
higher engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
Warning!
G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature gauge indicates that the engine is
overheated, do not open the hood. Move
away from vehicle and do not open the hood
until the engine has cooled. If necessary,
call the fire department.Warning!
G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition coils, spark plug sockets, diagnostic
socket) of the ignition system
with the engine running
while starting the engine
if ignition is “on” and the engine is
turned manually
Warning!
G
Be careful that you do not close the hood on
anyone.
iDo not use any special lubricant addi-
tives, as these may damage the drive
assemblies. Using special additives not
approved by Mercedes-Benz may
cause damage not covered by the
Mercedes-Benz Limited Warranty.
More information on this subject is
available at any Mercedes-Benz Light
Truck Center.
Page 333 of 539

332 OperationEngine compartment
Unscrew filler cap1 from filler neck.
Add engine oil as required. Be careful
not to overfill with oil.
Be careful not to spill any oil when adding.
Avoid environmental damage caused by oil
entering the ground or water.
Screw filler cap1 back on filler neck.
For more information on engine oil, see
“Technical data” (
page 481).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Light
Truck Center check the automatic trans-
mission.Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.
Warning!
G
In order to avoid any possibly 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 gauge indi-
cates 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 un-
der pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.
Page 334 of 539
333 Operation
Engine compartment
The coolant expansion tank is located on
the driver’s side of the engine compart-
ment.
1Coolant expansion tank
Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.
Continue turning the cap to the left and
remove it.
The coolant level is correct if the level
for cold coolant: reaches the top of
the indicator wall visible through
the filling opening
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap.
For more information on coolant, see the
“Technical data” section (
page 497).Windshield/rear window washer
system and headlamp cleaning
system*
The windshield washer reservoir is located
in the engine compartment.
1Cap
Fluid for the windshield washer system and
the headlamp cleaning system* is supplied
from the windshield washer reservoir. It
has a capacity of 8.1 US qt (7.7 l).
Page 411 of 539

410 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
?
(USA only)
±
(Canada only)
Visit workshop
There may be a malfunction in
the:
Fuel injection system
Ignition system
Exhaust system
Fuel system
Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
B
Coolant
Check level
The coolant level is too low.
Add coolant (
page 332).
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 can 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 en-
gine damage.
Page 412 of 539

411 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 symbol
Display messages
Possible cause
Possible solution
Ï
Coolant
Stop, engine off
The coolant is too hot.
Stop the vehicle and immediately turn off
the engine.
Only start the engine again after the mes-
sage disappears. You could otherwise
damage the engine.
Warning!
G
Driving when your engine is badly overheat-
ed 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.
Page 413 of 539
412 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
Ï
Coolant
Stop, engine off
The poly-V-belt could be broken.
Stop the vehicle and immediately turn off
the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Do not continue to drive the vehicle with
this message displayed. Doing so could
result in serious engine damage that is
not covered by the Mercedes-Benz Limit-
ed Warranty.
Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center.
Coolant
Visit workshop
The cooling fan for the coolant is
malfunctioning.
Observe the coolant temperature gauge
in the instrument cluster.
Have the fan replaced as soon as possi-
ble.