2008 MERCEDES-BENZ GL550 fuel cap

Contents
Replacing wiper blades ...................... 516
Front wiper blades ....................... 516
Rear wiper blade .......................... 517
Flat tire .............................................. 519
Preparing the vehicle.................... 519
Mounting the spare wheel ............ 520
Bleeding the fuel system
(diesel engine only) ............................ 527
Battery ............................................... 528
Disconnecting, removing,
reinstalling and
reconnecting the battery .............. 530
Charging the battery .................... 535
Jump starting ..................................... 536
Towing the vehicle ............................. 538
Installing towing eye bolt.............. 540
Stranded vehicle .......................... 542
Fuses ................................................. 543
Fuse box in engine compartment . 544
Fuse box in cargo compartment ... 544
Fuse box in
passenger compartment .............. 545
Emergency engine shut-down ...... 545
Technical data................................. 547
Parts service ...................................... 548
Warranty coverage............................. 549
Loss of Service and Warranty
Information Booklet ..................... 549
Identification labels ........................... 550
Layout of poly-V-belt drive ................. 552
GL 320 CDI .................................. 552
GL 450, GL 550............................ 552
Engine................................................ 553
Rims and tires.................................... 555
Same size tires ............................. 556
Minispare wheel ........................... 558
Electrical system ............................... 559
Main Dimensions ............................... 560
Weights.............................................. 561Fuels, coolants, lubricants ................. 562
Capacities .................................... 562
Engine oils ................................... 564
Engine oil additives ...................... 564
Air conditioning refrigerant .......... 564
Brake fluid.................................... 564
Premium unleaded gasoline
(gasoline engine).......................... 565
Fuel requirements ........................ 565
Gasoline additives
(gasoline engine).......................... 566
Coolants ...................................... 567
Windshield washer system and
headlamp cleaning system*......... 569
Index................................................. 571
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374 Operation
At the gas station
Refueling
The fuel filler flap is located on the
right-hand side of the vehicle towards the
rear. Locking/unlocking the vehicle with
the SmartKey or the SmartKey with
KEYLESS-GO* automatically
locks/unlocks the fuel filler flap.1Fuel filler flap
2Fuel filler cap
Turn off the engine.
Vehicles with SmartKey: Remove the
SmartKey from the starter switch.
Vehicles with KEYLESS-GO*: Open the
driver’s door (this puts the starter
switch in position0, same as with the
SmartKey removed from the starter
switch). The driver’s door then can be
closed again.
Warning!G
Gasoline and diesel fuels are highly flamma-
ble and poisonous. They burn violently and
can cause serious personal injury.
Never allow sparks, flame or smoking mate-
rials near gasoline or diesel fuel!
Turn off the engine before refueling.
Whenever you are around gasoline or diesel
fuel, avoid inhaling fumes and skin or cloth-
ing contact, extinguish all smoking materi-
als.
Direct skin contact with gasoline or diesel
fuels and the inhalation of gasoline or diesel
fuel vapors are damaging to your health.
Warning!G
Do not fill diesel tanks with gasoline. Do not
mix diesel fuel with gasoline. Otherwise the
fuel system and engine could be damaged.
In addition, the vehicle could catch fire.
!Damage resulting from mixing gasoline with
diesel is not covered by the Mercedes-Benz
Limited Warranty.
!Diesel engine: When filling the diesel fuel
tank using fuel containers, place a filling filter, a
suede cloth or a clean flannel cloth as a filter.
Otherwise, particles from the fuel container
could clog the fuel lines and/or the diesel injec-
tion system.
iIn case the central locking system does not
release the fuel filler flap, see “Fuel filler flap”
(
page 497).
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375 Operation
At the gas station
Briefly push on fuel filler flap1 at the
position indicated by the arrow.
Fuel filler flap1 opens slightly.
Open fuel filler flap1 completely.
Turn fuel filler cap2 counterclock-
wise and hold on to it until possible
pressure is released.
Take off fuel filler cap2.
Set fuel filler cap2 on fuel filler
flap1 as shown.
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 over-
fill.
Replace fuel filler cap2 by turning it
clockwise until it audibly engages.
Close fuel filler flap1.
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 noz-
zle, which could cause personal injury.
iMake sure to close the fuel filler flap before
locking your vehicle as the flap locking pin
prevents closing after you have locked the
vehicle.
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 439).
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 565), see “Fuel requirements”
(
page 565), 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.

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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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395 Operation
Tires and wheels
Tire inflation pressure changes by approxi-
mately 1.5 psi (0.1 bar) per 18°F (10°C) of
air temperature change. Keep this in mind
when checking tire inflation pressure
where the temperature is different from
the outside temperature.
Checking tire inflation pressure
Regularly check your tire inflation pressure
at least once a month.
Check and adjust the tire inflation
pressure when the tires are cold. The tires
can be considered cold if the vehicle has
been parked for at least 3 hours or driven
less than 1 mile (1.6 km).
If you check the tire inflation pressure
when the tires are warm (the vehicle has
been driven for several miles or sitting less
than 3 hours), the reading will be
approximately 4 psi (0.3 bar) higher than
the cold reading. This is normal. Do not let
air out to match the specified cold tire
inflation pressure. Otherwise, the tire will
be underinflated.Checking tire inflation pressure
manually
Follow the steps below to achieve correct
tire inflation pressure:
Remove the cap from the valve on one
tire.
Firmly press a tire gauge onto the
valve.
Read tire inflation pressure on tire
gauge and check against the recom-
mended tire inflation pressure on the
Tire and Loading Information placard
on the driver’s door B-pillar
(
page 388) or, if available, the inside
of the fuel filler flap. If necessary, add
air to achieve the recommended tire in-
flation pressure.
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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396 Operation
Tires and wheels
Install the valve cap.
Repeat this procedure for each tire.Run Flat Indicator (Canada only)
While the vehicle is being driven, the Run
Flat Indicator monitors the set tire inflation
pressures by evaluating each wheel’s rota-
tional speed. This allows the system to de-
tect a significant loss of pressure in a tire.
If a wheel’s rotational speed changes due
to falling tire inflation pressure, you will
see a corresponding warning message in
the multifunction display.
The Run Flat Indicator may function in a
restricted manner or with a delay

if snow chains are mounted to the
vehicle

in presence of ice and snow

if you are driving on a loose surface
(e.g. sand or gravel)

if you are driving in a very sporty
manner (involving rapid acceleration or
high speeds in curves)
iIf you have overfilled the tire, release tire in-
flation pressure by pushing the metal stem of the
valve with e.g. a tip of a pen. Then recheck the
tire inflation pressure with the tire gauge.Warning!G
When the multifunction display shows the
message
Tire Pressure Check Tires,
one or more of your tires is significantly un-
derinflated. You should stop and check your
tires as soon as possible, and inflate them to
the proper tire inflation pressure as indicat-
ed on the vehicle’s Tire and Loading
Information placard or, if available, on the
tire inflation pressure label. Driving on a sig-
nificantly under-inflated tire causes the tire
to overheat and can lead to tire failure. Un-
derinflation also reduces fuel efficiency and
tire tread life, and may affect the vehicle’s
handling and stopping ability. Each tire, in-
cluding the spare, should be checked
monthly when cold and set to the recom-
mended tire inflation pressure as specified
on the Tire and Loading Information placard
on the driver’s door B-pillar (
page 388) or,
if available, on the tire inflation pressure la-
bel located on the inside of the fuel filler flap
(
page 374).

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416 Operation
Tires and wheels
Bar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi)
to 1 bar; there are 100 kilopascals (kPa)
to 1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least 3 hours or
driven no more than 1 mile (1.6 km).
Curb weight
The weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if so
equipped, air conditioning and additional
optional equipment, but without passen-
gers and cargo.DOT (Department of Transportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross Axle Weight Rating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
certification label located on the driver’s
door B-pillar.
GTW (G
ross Trailer Weight)
The GTW is the weight of the trailer plus
the weight of all cargo, equipment, luggage
etc. loaded on the trailer.GVW (G
ross Vehicle Weight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GVW must never exceed the
GVWR indicated on the certification label
located on the driver’s door B-pillar.
GVWR (G
ross Vehicle Weight Rating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
certification label located on the driver’s
door B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are 100 kilopascals
(kPa) to 1 bar.
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440 Practical hints
What to do if …
ProblemPossible cause/conse-
quenceSuggested solution
?(USA only)
±(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.A loss of pressure has been
detected in the fuel system.
The fuel cap may not be closed
properly or the fuel system
may be leaky.Check the fuel cap (page 374).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
Vehicles with diesel engine:
Your fuel tank is empty.After refueling start, turn off and
restart the engine three or four times in
succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.
lThe red distance warning lamp comes on
while driving and you hear a warning sound.You are gaining too rapidly on
the vehicle ahead of you.Apply the brakes immediately.
Carefully observe the traffic situation.
You may need to brake or maneuver to
avoid hitting an obstacle.
The Distronic* has recognized
a stationary obstacle on your
probable line of travel.
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