2008 MERCEDES-BENZ G55AMG engine coolant

265
Operation
At the gas station
Only fill your tank until the filler nozzle
unit cuts out –
do not top off or
overfill .
Replace fuel filler cap 2 by turning it
clockwise until it audibly engages.
Close fuel filler flap 1.
You should hear the latch close shut.
Check regularly and before a long trip
For information on quantities and require-
ments of operating agents, see “Fuels,
coolants, lubricants, etc.” (
page 420).
Open the hood (page 267).
G 500
1 Coolant
2 Brake fluid
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 caus e personal injury.
!When refueling the vehicle, make certain
that no gasoline comes into contact with the rear
side marker to prevent damaging the lens.
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 ? malfunction indicator
lamp (USA only) or the ± malfunction indica-
tor lamp (Canada only) comes on.
For more information, see “Practical hints”
(
page 328).
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.
Please contact gas station personnel in case la-
bels on the pump cannot be found.
For more information on gasoline, see “Premium
unleaded gasoline” (
page 424), refer to the
Factory Approved Service Products pamphlet
(USA only), or contact an authorized
Mercedes-Benz Light Truck Center.
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266 Operation
At the gas station
G55AMG
1Coolant
2 Brake fluid Brake fluid
Coolant
For normal replenishing, use water
(potable water quality).
For more information, see “Coolant level”
(
page 274) and see “Fuels, coolants, lu-
bricants, etc.” (
page 420). Engine oil level
For more information on engine oil, see
“Engine oil” (
page 269).
Windshield/rear window washer sys-
tem and headlamp cleaning system
For more information on refilling the
washer reservoir, see “Windshield/rear
window washer syst em and headlamp
cleaning system” (
page 275).
Vehicle lighting
Check function and cleanliness.
For information on replacing light bulbs,
see “Replacing bulbs” (
page 375).
For more information, see “Exterior lamp
switch” (
page 117).
Tire inflation pressure
For more information, see “Checking tire
inflation pressure” (
page 288).
!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 “Practical hints”
(
page 326) and see “Brake fluid”
(
page 423).
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267
Operation
Engine compartment
 Engine compartment
Hood
Opening
Warning!G
Do not pull the release lever while the vehi-
cle is in motion. Otherwise the hood could
be forced open by passing air flow.
This could cause the hood to come loose
and injure you and others.
Warning!G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature display 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
You could be injured when the hood is open
– even when the engi ne is switched off.
Parts of the engine can become very hot. To
prevent burns, let the engine cool off com-
pletely before touching any components on
the vehicle. Comply with all relevant safety
precautions.
Warning!G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
The radiator fan may continue to run for
approximately 30 seconds or even restart
after the engine has b een turned off. Stay
clear of fan blades.
Warning!G
The engine is equipped with a transistorized
ignition system. Becaus e of the high voltage,
it is dangerous to touch any components
(ignition 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
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274 Operation
Engine compartment
Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze.
When checking the coolant level,

the vehicle must be parked on level
ground

the coolant temperature must be be-
low 158°F (70°C)The coolant expansion tank is located on
the passenger side of the engine compart-
ment.
1 Cap
Warning!G
In order to avoid any potentially 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 display
indicates 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
approximately 1/2turn to relieve excess
pressure. If opened immediately, scald-
ing hot fluid and steam will be blown out
under pressure.

Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene
glycol which may burn if it comes into
contact with hot engine parts.
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275
Operation
Engine compartment
Using a rag, turn cap
1 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning cap 1 counterclock-
wise and remove it.
The coolant level is correct if the level

for cold coolant: reaches the top of
the mark (plastic bridge) visible
through the filling opening

for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace cap 1 on the filler neck.
Tighten cap 1 clockwise until you
hear it click three times.
For more information on coolant, see
“Coolants” (
page 425). Windshield/rear window washer
system and headlamp cleaning system
The windshield washer reservoir is located
on the passenger side of the engine
compartment.
1 Cap Fluid for the windshield/rear window
washer system and the headlamp cleaning
system is supplied from the windshield
washer reservoir. It
has a capacity of
7.9 US qt (7.5 l).
During all seasons, add MB Windshield
Washer Concentrate “MB SummerFit” to
water. Premix the windshield washer fluid
in a suitable container.
Warning!G
Washer solvent/antifreez e is highly flamma-
ble. Do not spill wash er solvent/antifreeze
on hot engine parts, because it may ignite
and burn. You could be seriously burned.
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345
Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
;(USA only)
! (Canada only)
Release
parking
brakeYou are driving with the parking brake
set.Release the parking brake
(
page 55).
2Brake
wearThe brake pads have reached their wear
limit.Have the brake pads replaced as
soon as possible.
BTop up
coolant
See
Operator’s
ManualThe coolant level is too low.Add coolant (page 274).
If you have to add coolant frequently,
have the cooling system checked at
an authorized Mercedes-Benz Light
Truck Center.
!Brake pad thickness must be visually
checked by a qualified technician at the intervals
specified in the Maintenance Booklet.
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 could be seriously burned.
!Do not ignore the low engine coolant level
warning. Extended driving with this 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 engine damage.
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346 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant
Stop, turn
engine offThe coolant is too hot.
Among other possible causes, the
poly-V-belt could be broken.Stop the vehicle in a safe location or as soon
as it is safe to do so.
Apply the parking brake (page 62).
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.
Contact an authorized Mercedes-Benz Light
Truck Center.
If it is in order:
Wait for the message to disappear before
restarting the engine.
Doing otherwise could result in serious engine
damage that is not covered by the
Mercedes-Benz Limited Warranty.
(Continued on next page)
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347
Practical hints
What to do if …
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
Observe the coolant temperature gauge in the
instrument cluster (
page 26).
If the temperature rises again:
Contact an authorized Mercedes-Benz
Light Truck Center immediately.
Warning!G
Driving when your engine is overheated can
cause some fluids which may have leaked
into the engine compartment to catch fire.
You could be se riously burned.
Steam from an overheated engine can cause
serious burns and can oc cur just by opening
the 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 engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.
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