2008 MERCEDES-BENZ GL450 flat tire

357 Operation
Driving instructions
Checklist before off-road driving
Engine oil level

Check the engine oil level with the oil
dipstick (
page 380).
Only with a proper oil level can the
vehicle obtain a trouble-free oil supply,
even on steep gradients.
!Observe the following during off-road
driving:

Keep doors, tailgate, windows, and
tilt/sliding sunroof* closed whenever driving
off-road.

Adjust vehicle speed to condition of terrain.
The more uneven, rutty and steeper the ter-
rain, the lower the speed should be. Drive
through water slowly at an even speed,
avoiding a bow wave.

Be especially careful when driving in un-
known territory. It may be necessary to get
out of the vehicle and scout the path you in-
tend to take.

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

Before driving through water, determine its
depth.

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

In sandy soil, drive at a steady speed as al-
lowed by conditions. This helps overcome
the vehicle rolling resistance and reduces
the likelihood of the vehicle sinking into the
ground.

Do not initiate jumps with the vehicle. It
interrupts the forward momentum of the
vehicle.

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

Do not shift automatic transmission to
positionN.
Warning!G
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure (
page 395) before continuing
your trip. Driving with reduced tire inflation
pressure increases the risk of losing control
of the vehicle and rolling over.
!If the engine oil level warning lamp
(
page 473) comes on while driving, stop the
vehicle in a safe location or as soon at is safe to
do so. Check the engine oil level (
page 380).
The engine oil level warnings 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.
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358 Operation
Driving instructions
Tires

Check the tread depth and maintain
specified tire inflation pressure
(a placard with the recommended tire
inflation pressures is located on the
driver’s door B-pillar (
page 388)).

Check tires for possible damage and
remove foreign objects.

Replace missing valve caps.
Rims

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

Check if the vehicle jack (page 492)
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 angle
1 Overhang angle, front
2Overhang angle, rear

Comply with the warnings
(
page 355) and rules for off-road
driving (
page 356).

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 100% grade which is
equivalent to a slope angle of
45 degrees. Keep in mind that the
climbing ability of the vehicle depends
on terrain conditions.
Vehicles with air sus-
pension program12
Raised level34°28°
Highway29°23°
Vehicles with
enhanced off-road
package*12
Off-road-level 336°30°
Off-road-level 234°28°
Off-road-level 131°25°
Highway29°23°
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362 Operation
Driving instructions
When driving over tree stumps, big rocks
and other obstacles, observe the following
rules:

Make sure the off-road driving program
(
page 277) or if equipped the LOW
RANGE mode* (
page 201) is
switched on.

Avoid high engine speeds.

Shift automatic transmission to
position1 (
page 197).

Check the vehicle clearance before
crossing obstacles.

Cross obstacles (e.g. tree stumps or
big rocks) very slowly by aiming one of
the front wheels at the center of the ob-
stacle, and repeat same with the rear
wheel.Driving on sand
When driving on sand, observe the follow-
ing rules:

Set the raised level (page 279).

Avoid high engine speeds.

Shift automatic transmission into a
gear range that is appropriate for the
terrain.

In sandy soil, drive at a steady speed as
conditions permit. This helps overcome
the vehicle rolling resistance and re-
duce the likelihood of the vehicle sink-
ing into the ground.

Drive in tracks of other vehicles if they
are not too deep and you have suffi-
cient clearance.
Ruts
A number of off-road tracks or other by-
ways have deep ruts which can cause the
underbody to come in contact with the
ground.

Make sure the off-road driving program
(
page 277), or if equipped, the LOW
RANGE mode* (
page 201) is
switched on.

Set the raised level (page 279).!Special attention is needed when you cross
obstacles on a steep incline.
The vehicle could slide sideways as a result of its
possible slanted position which in turn may
result in the vehicle tipping or rolling over.
Warning!G
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure (
page 395) before continuing
your trip. Driving with reduced tire inflation
pressure increases the risk of losing control
of the vehicle and rolling over.
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377 Operation
At the gas station
Brake fluid
Coolant
For normal replenishing, use water (pota-
ble water quality).
For more information, see “Coolant level”
(
page 381) and see “Fuels, coolants, lu-
bricants” (
page 562).Windshield/rear window washer
system and headlamp cleaning
system*
For more information on refilling the wash-
er reservoir, see “Windshield/rear window
washer system and headlamp cleaning
system*” (
page 383).
Vehicle lighting
Check function and cleanliness. For infor-
mation on replacing light bulbs, see “Re-
placing bulbs” (
page 504).
For more information, see “Exterior lamp
switch” (
page 143).
Tire inflation pressure
For more information, see “Checking tire
inflation pressure” (
page 395).
!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. Notify an
authorized Mercedes-Benz Light Truck Center
immediately. Do not add brake fluid as this will
not solve the problem. For more information, see
“Brake fluid” (
page 564).
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384 Operation
Tires and wheels
Contact an authorized Mercedes-Benz
Light Truck Center for information on test-
ed and recommended rims and tires for
summer and winter operation. They can
also offer advice concerning tire service
and purchase.Important guidelines

Only use sets of tires and rims of the
same type and make.

Tires must be of the correct size for the
rim.

Break in new tires for approximately
60 miles (100 km) at moderate
speeds.

Regularly check the tires and rims for
damage. Dented or bent rims can
cause tire inflation pressure loss or
damage to the tire beads.

If vehicle is heavily loaded, check tire
inflation pressure and correct as
required.

Do not allow your tires to wear down
too far. Adhesion properties on wet
roads are sharply reduced at tread
depths of less than
1/8in (3 mm).

When replacing individual tires, you
should mount new tires on the front
wheels first (on vehicles with
same-sized wheels all around).
Warning!G
Replace rims or tires with the same designa-
tion, manufacturer and type as shown on the
original part. Contact an authorized
Mercedes-Benz Light Truck Center for fur-
ther information. If incorrectly sized rims
and tires are mounted:

The wheel brakes or suspension
components can be damaged.

The operating clearance of the wheels
and the tires may no longer be correct.
Warning!G
Worn, old tires can cause accidents. If the
tire tread is badly worn, or if the tires have
sustained damage, replace them.
When replacing rims, only use genuine
Mercedes-Benz wheel bolts specified for the
particular rim type. Failure to do so can
result in the bolts loosening and possibly an
accident.
Retreaded tires are not tested or recom-
mended by Mercedes-Benz, since previous
damage cannot always be recognized on re-
treads. The operating safety of the vehicle
cannot be assured when such tires are used.
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385 Operation
Tires and wheels
Tire care and maintenance
Regularly check your tire inflation pressure
at least once a month. For more informa-
tion on checking tire inflation pressure,
see “Recommended tire inflation pres-
sure” (
page 393).Tire inspection
Every time you check your tire inflation
pressure, you should also inspect your
tires for the following:

excessive treadwear (page 386)

cord or fabric showing through the
tire’s rubber

bumps, bulges, cuts, cracks or splits in
the tread or side of the tire
Replace the tire if you find any of the above
conditions.
Make sure you also inspect the spare tire
periodically for condition and inflation.
Spare tires will age and become worn over
time even if never used, and thus should be
inspected and replaced when necessary.Life of tire
The service life of a tire is dependent upon
varying factors including but not limited to:

Driving style

Tire inflation pressure

Distance driven
Warning!G
Regularly check the tires for damage. Dam-
aged tires can cause tire inflation pressure
loss. As a result, you could lose control of
your vehicle.
Worn, old tires can cause accidents. If the
tire tread is badly worn, or if the tires have
sustained damage, replace them.
Warning!G
Tires and spare tire should be replaced after
6 years, regardless of the remaining tread.
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387 Operation
Tires and wheels
Direction of rotation
Unidirectional tires offer added advantag-
es, such as better hydroplaning perfor-
mance. 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 (spinning) of
the tire.Loading the vehicle
Two labels on your vehicle show how much
weight it may properly carry.
1) The Tire and Loading Information
placard can be found on the driver’s
door B-pillar. This placard tells you im-
portant information about the number
of people that can be in the vehicle and
the total weight that can be carried in
the vehicle. It also contains information
on the proper size and recommended
tire inflation pressures for the original
equipment tires on your vehicle.2) The certification label, also found on
the driver’s door B-pillar tells you about
the gross weight capacity of your vehi-
cle, called the Gross Vehicle Weight
Rating (GVWR). The GVWR includes the
weight of the vehicle, all occupants,
fuel and cargo. The certification label
also tells you about the front and rear
axle weight capacity, called the Gross
Axle Weight Rating (GAWR). The GAWR
is the total allowable weight that can be
carried by a single axle (front or rear).
Never exceed the GVWR or GAWR for
either the front axle or rear axle.
iSpare wheels may be mounted against the
direction of rotation (spinning) even with a unidi-
rectional tire for temporary use only until the reg-
ular drive wheel has been repaired or replaced.
Always observe and follow applicable temporary
use restrictions and speed limitations indicated
on the spare wheel.
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393 Operation
Tires and wheels
Recommended tire inflation pressure
Your vehicle is equipped with the Tire and
Loading Information placard located on the
driver’s door B-pillar (
page 388).
The tire inflation pressure should be
checked regularly and should only be ad-
justed on cold tires. The tires can be con-
sidered cold if the vehicle has been parked
for at least 3 hours or driven less than
1 mile (1.6 km).Follow recommended cold tire inflation
pressures listed on Tire and Loading
Information placard on the driver’s door
B-pillar.
Keeping the tires properly inflated
provides the best handling, tread life and
riding comfort.
In addition to the Tire and Loading
Information placard on the driver’s door
B-pillar, also consult the tire inflation
pressure label (if available) on the fuel filler
flap (page 374) for any additional infor-
mation pertaining to special driving situa-
tions. For more information, see
“Important notes on tire inflation pressure”
(
page 394).
Warning!G
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 over-
heated.
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.
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.
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