1997 MERCEDES-BENZ ML320 engine

201 Operation
Driving instructions
Special driving features for off-road
driving
The following driving features are available
for specific kind of operation:

LOW RANGE mode (
page 125)


LOW RANGE – ABS (
page 77)


LOW RANGE – 4-ETS (
page 80)


LOW RANGE – ESP (
page 81)
Off-road driving rules
Engage the LOW RANGE mode before driv-
ing under off-road conditions
(
page 125).
Fasten items being carried as securely as
possible (
page 157).Checklist before off-road driving
Tires


Check the tread depth and maintain
specified tire pressure (see tire pres-
sure label inside the fuel filler flap).


Check tires for possible damage and
remove foreign objects.


Replace missing valve caps.
iWe recommend keeping doors, liftgate,
windows, and sliding / pop-up roof*
closed whenever driving in off-road
mode.
!Observe the following during off-road
driving:

Adjust vehicle speed to condition of
terrain. The more uneven, rutty and
steeper the terrain, the lower the
speed should be


Watch out for obstacles, such as
rocks, holes, tree stumps and ruts.


Be especially careful when driving
in unknown territory. It may be nec-
essary to get out of the vehicle and
scout the path you intend to take.


Before driving through water, deter-
mine is depth.


Do not stop vehicle while immersed
in water, and do not shut off the
engine.


In sandy soil, please drive at a
steady speed as allowed by condi-
tions. This helps overcome the vehi-
cle rolling resistance and reduces
the likelihood of the vehicle sinking
into the ground.


Do not initiate jumps with the vehi-
cle. It interrupts the forward mo-
mentum of the vehicle.


Always drive onto slopes with the
the engine running and the vehicle
in gear.

202 OperationDriving instructionsRims

Dented or bent rims can cause tire
pressure loss and damage the tire
beads. For this reason, check and, if
necessary, change rims before driving
off-road.
Vehicle tool kit


Check if the vehicle jack is functional.


In all cases take the vehicle tool kit, a
strong tow rope, a shovel and a small
plank (to put under the vehicle jack on
sandy soil) with you.
Driving in steep terrain
Slope angle1 25°
226°

Switch to LOW RANGE mode before
starting to drive up or down steep in-
clines (
page 125).


Driving on embankments, slopes and
other steep inclines should only be
done straight up or downhill, i.e. in the
line of gravity. Maximum vehicle climb-
ing ability is a 60% grade.


Do not drive along the side of a slope
(danger of vehicle rollover). If in doing
so, the vehicle begins to show a ten-
dency to roll, immediately steer into a
line of gravity (straight up or downhill).


To help avoid the vehicle rolling over,
never turn it around on steep inclines.
If the vehicle cannot complete the at-
tempted climb, back it down in reverse
gear.


Utilize the engine’s braking power
when descending a slope, observe the
engine speed (do not overview the en-
gine). Apply the service brake as need-
ed.


Check the brakes after a lengthy down-
grade drive.
Traction in steep terrain


Be easy on the accelerator and watch
for continuous wheel traction when
driving in steep terrain.
The 4-ETS helps greatly when starting
out on a steep incline when the front
wheels have then the tendency to slip
due to the weight shifting away the
front axle.iAvoid excessive engine speeds – drive
with moderate engine speeds
(max. 3000 RPM).
Select gear range2 or1 on the auto-
matic transmission (
page 121).

204 OperationDriving instructions

Switch off the exterior lamps as well as
the climate control.


Select gear range1 on the automatic
transmission (
page 121).


Enter the water only at a shallow spot,
driving at walking speed.


Do not stop vehicle while immersed in
water, and do not shut off the engine.
There is a very high level of driving re-
sistance in water. The surface is slip-
pery and may not be firm, making
pulling away in water difficult and dan-
gerous.


Clean mud off the tire tread after driv-
ing through water.


To dry the brakes, apply pressure to the
brake pedal several times after leaving
the water.
Crossing obstacles
!Never accelerate before driving into
the water. The bow wave could force
water into the engine and auxiliary
equipment, thus damaging them.
!Obstacles can damage the vehicle
undercarriage or suspension compo-
nents. If possible use the assistance of
a second person outside the vehicle to
scout the path you intend to take and
check for adequate ground clearance
when you cross obstacles with your ve-
hicle. The person assisting you outside
the vehicle should always be a safe dis-
tance away from the vehicle and posi-
tioned so that he or she cannot get hurt
in case of any unexpected vehicle
movement.
After off-road driving or crossing obsta-
cles, inspect vehicle for any damage,
especially vehicle undercarriage and
suspension components. Failure to do
so can adversely affect the vehicle's fu-
ture performance, including increased
chance of an accident.

206 OperationDriving instructionsOff-road driving increases strain on the
vehicle.
We recommend that you inspect the vehi-
cle for possible damage after each off-road
trip. Recognizing any damage and a subse-
quent timely repair reduces the chance of
a possible breakdown or accident later on.
Proceed as follows:

Switch off the LOW RANGE mode
(page 125).


Remove excessive dirt from tires,
wheels, wheel housings, and under-
body.
For instance, after driving in mud, clean
the radiator, chassis, engine, brakes,
and wheels from extreme dirt using a
strong jet of water.


Inspect frame, oil pan, brake hoses,
etc., as well as vehicle underbody for
possible damage.


Check tires for possible damage, clean
all exterior lamps, and conduct a brake
test.


Check for brush or branches caught in
the undercarriage.
They could increase the possibility of a
fire, as well as cut fuel and / or brake
lines, puncture rubber bellows of the
axles or drive shafts.


After continued operation in mud,
sand, water or other dirty conditions
clean the brake discs, wheels, brake
pads and check and clean axle joints.
Trailer towingWarning!
G
Failure to use proper equipment and driving
technique can result in a loss of vehicle con-
trol when towing a trailer.
Improper towing or failure to follow the in-
structions contained in this guide can result
in serious injury. Follow the guidelines be-
low carefully to assure safe trailer operation.
Ask your authorized Mercedes-Benz Light
Truck Center should you require an explana-
tion of information contained in this guide.

210 OperationDriving instructions

The vehicle and trailer combination is
heavier, and therefore is limited in ac-
celeration and climbing ability, and re-
quires longer stopping distances.
I t i s m o r e p r o n e t o r e a c t i n g t o s i d e w i n d
gusts, and requires more sensitive
steering input.


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 transmission hunts between
gears on inclines, manually shift to a
lower gear (select 4, 3, 2 or 1).
A lower gear and reduction of speed re-
duces the chance of engine overload-
ing and / or overheating.


On very steep inclines, not manageable
with gear selector lever in position1,
switch transfer case to LOW RANGE
mode (
page 125).


When going down a long hill, shift into
a lower gear and use the engine’s brak-
ing effect.
Avoid riding the brakes, thus overheat-
ing the vehicle and trailer brakes.


If the engine coolant rises to an ex-
tremely high temperature (coolant tem-
perature needle approaching the red
zone) 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 hot position.


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 re-
turn to your lane.
!If the trailer should begin to sway, re-
duce the vehicle’s speed and use the
brake controller by hand to straighten
out the vehicle and trailer.
In no case should you attempt to
straighten out the tow vehicle and trail-
er by increasing the speed or overstee-
ring and stepping on the brakes.

212 OperationDriving instructionsTelephones and two-way radios
Radio transmitters, such as a portable tele-
phone or a citizens band unit should only
be used inside the vehicle if they are con-
nected to an antenna that is installed on
the outside of the vehicle.
Refer to the radio transmitter operation in-
structions regarding use of an external an-
tenna.
Catalytic converter
Your Mercedes-Benz is equipped with
monolithic-type catalytic converters, an
important element in conjunction with the
oxygen sensors to achieve substantial con-
trol of the pollutants in the exhaust emis-
sions. Keep your vehicle in proper
operating condition by following our rec-
ommended maintenance instructions as
outlined in your Service Booklet.
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 ac-
cording to factory specifications. Any ad-
justments on the engine should, therefore,
be carried out only by qualified
Mercedes-Benz Light Truck Center autho-
rized technicians. Engine adjustments
should not be altered in any way. More-
over, the specified service jobs must be
Warning!
G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system, pos-
sibly resulting in an accident and / or
personal injury.
!To prevent damage to the catalytic con-
verters, use only premium unleaded
gasoline in this vehicle.
Any noticeable irregularities in engine
operation should be repaired promptly.
Otherwise, excessive unburned fuel
may reach the catalytic converter,
causing it to overheat and start a fire.
Warning!
G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.

213 Operation
Driving instructions
carried out regularly according to
Mercedes-Benz servicing requirements.
For details refer to the Service Booklet.
Coolant temperature
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise to approx. 248°F
(120°C).
The engine should not be operated with
the coolant temperature in the red zone.
Doing so may cause serious engine dam-
age 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, and inhaling it can cause uncon-
sciousness and lead to 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.
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.

215 Operation
At the gas station

Replace the fuel cap by turning it to the
right.
You will hear when the fuel cap is tight-
ened.

Close the fuel filler flap.
Check regularly and before a long trip
Open the hood (
page 217)
1Engine oil level
2Coolant level
For normal replenishing, use water (po-
table water quality). More information
on the coolant level can be found in the
“Operation” section (
page 222).
3Brake fluid
4Windshield washer system and
headlamp cleaning system*
More information on filling the reser-
voir can be found in the “Operation”
section (
page 224).
iUse only 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.
More information on gasoline can be
found in the Factory Approved Service
Products pamphlet.
iLeaving the engine running and the fuel
cap open can cause the yellow fuel
tank reserve warning lamp to flash and
the? lamp to illuminate.
See also “Practical hints” section
(page 248).