2012 MERCEDES-BENZ G-CLASS SUV engine

Problems with the fuel and fuel tank
Problem Possible causes/consequences and
M Solutions
Fuel is leaking from the
vehicle.
G
Risk of explosion or fire
The fuel line or the fuel tank is defective.
X Turn the key to position 0(Ypage 143) in the ignition lock
immediately and remove it.
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop. The fuel filler flap can-
not be opened. The fuel filler flap is not unlocked.
or
The key batteries are discharged.
X
Unlock the vehicle (Y page 68).
or
X Unlock the vehicle using the emergency key element
(Y page 70).
X Open the rear door.
X Manually unlock the fuel filler flap using the emergency release
(Y page 158). The fuel filler flap is unlocked, but the opening mechanism is jam-
med.
X
Manually unlock the fuel filler flap using the emergency release
(Y page 158).
X Consult a qualified specialist workshop. The engine does not
start. The fuel tank of a vehicle with a diesel engine has been run com-
pletely dry.
X
Refuel the vehicle with at least 5litres of diesel.
X Turn the ignition on for around 10 seconds(Y page 143).
X Start the engine continuously for up to 40 seconds until it runs
smoothly.
If the engine does not start:
X Turn the ignition on again for approximately
10 seconds(Y page 143).
X Start the engine again continuously for up to 40 seconds until
it runs smoothly.
If the engine does not start after three attempts:
X Consult a qualified specialist workshop. Refuelling
159Driving and parking Z

AdBlue
®
Important notes on use To function properly, BlueTEC exhaust gas
aftertreatment 1
mus tbe operated with the
reducing agent AdBlue ®
.
When the supply of AdBlue ®
is almost used
up, the Refill AdBlue See Owner's Man‐
ual message is shown in the multifunction
display. Awarning tone also sounds.
If the Refill AdBlue No start in: .. km message is shown in the multifunction dis-
play, you can still driv ethe vehicle over the
distance shown. Awarning tone also sounds.
If the AdBlue ®
is no ttopped up, you will sub-
sequently be unable to start the engine.
After receiving the warning message, it is
preferable to fill the AdBlue ®
tank with
10 litres of AdBlue ®
.Int his way, you can
ensure that the AdBlue ®
supply lasts until the
next regular service date.
Further information about BlueTEC exhaust
gas aftertreatment and about AdBlue ®
can
be obtained from any Mercedes-Ben zService
Centre.
Topping up AdBlue ®!
Only use AdBlue ®
in accordance with
ISO 22241. Do not mix any additives with
AdBlue ®
, and do not dilute AdBlue ®
with
water. This may destroy the BlueTEC
exhaust gas aftertreatmen tsystem.
! In order to fill the AdBlue ®
tank, the vehi-
cle mus tbe parked on a level surface. The
AdBlue ®
tank can only be filled as intended
with the vehicle parked on a level surface.
Fluctuations in capacity will thus be avoi-
ded. Filling a vehicle standing on an uneven
surface is not permitted. There is a danger
of overfilling, which can cause damage to
BlueTEC exhaust gas aftertreatmen tcom-
ponents. !
Do not fill the AdBlue ®
container with a
pump nozzle.
! If there are steep gradients while driving
off-road, a sufficient filling level in the
AdBlue ®
tank must be ensured. Make sure
for this reason that there is a minimum fill
level of ten litres before driving off-road.
! Surfaces which have come into contact
with AdBlue ®
while refilling should be
rinsed immediately with water, or remove
AdBlue ®
with a moist cloth and cold water.
If AdBlue ®
has already crystallised, use a
sponge and cold water to clean the area.
AdBlue ®
residue crystallises after a certain
amount of time and soils the affected sur-
faces.
! AdBlue ®
is not a fuel additive and must
not be added to the fuel tank.IfA dBlue®
is
added to the fuel tank, this can lead to
engine damage.
If you open the AdBlue ®
tank cap, small
amounts of ammonia vapour may be
released.
Ammonia vapours have a pungen todour and
are particularly irritating to:
R skin
R mucous membranes
R eyes
You may experience a burning sensation in
your eyes, nose and throat, as well as cough-
ing and watering of the eyes.
Do not inhale any ammonia vapours that may
be released. Fill the AdBlue ®
tank only in well-
ventilated areas.
1 BlueTEC vehicles only. 160
RefuellingDriving and parking

X
Turn AdBlue ®
refill bottle :anti-clockwise
and remove it.
X Screw the protective cap onto AdBlue ®
refill bottle :again.
Closing the AdBlue ®
filler cap and fuel
filler flap X
Fit blue AdBlue ®
filler cap ;on the filler
neck and turn it clockwise.
X To close the fuel filler flap, press it in the
direction of arrow :.
i The Refill AdBlue See Owner's Man‐
ual message goes out at the latest after
a driving distance of several kilometres.
i Have the AdBlue ®
supply topped up fully
if necessary. Mercedes-Benz recommends
that you use a qualified specialist workshop
for this purpose. Parking
Important safety notes
G
WARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example:
R releasing the parking brake
R shifting the automatic transmission out of
the parking position P
R starting the engine.
They could also operate the vehicle's equip-
ment.T here is a risk of an accident and injury. When leaving the vehicle, always take the key
with you and lock the vehicle. Never leave
children unsupervised in the vehicle.
G
WARNING
If flammable materials such as leaves, grass
or twigs are exposed to prolonged contact to
parts of the exhaust system that heat up, they
could ignite. There is a risk of fire.
Park the vehicle so that no flammable mate-
rials come into contact with parts of the vehi-
cle which are hot. Take particular care not to
park on dry grassland or harvested grain
fields. G
WARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or not at all. This could affect,
for example, the power steering and the brake
boosting effect.Y ou will require considerably
more effort to steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
To ensure that the vehicle is secured against
rolling away unintentionally:
R the parking brake must be applied.
R the transmission must be in position Pand
the key must be removed from the ignition
lock
R the transfer case must not be in position
N.
R on uphill or downhill gradients, turn the
front wheels towards the kerb. Switching off the engine
Important safety notes G
WARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or not at all. This could affect,
for example, the power steering and the brake Parking
163Driving and parking
Z

boosting effect. You will require considerably
more effor
tto steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
Vehicles with automatic transmission X
Shift the transmission to position P.
X Turn the key to position 0in the ignition
lock (Y page 143) and remove it.
The immobiliser is activated.
X Apply the parking brake firmly.
X Turn the steering wheel until the steering
wheel lock engages.
i If you switch the engine off with the trans-
mission in position Ror D, the automatic
transmission shifts to Nautomatically.
If you then open one of the front doors or
remove the key from the ignition, the auto-
matic transmission shifts to P.
If you shift the automatic transmission to
N before switching off the engine, the auto-
matic transmission remains in Neven if a
door is opened.
i The key can only be removed if the auto-
matic transmission is in position P.Parking brake
i
When you apply parking brake ;to brake
the vehicle, the brake lamps do not light up.
X To apply: pull parking brake ;up firmly.
Parking brake ;is applied. If the key is in position
1or 2in the ignition
lock, the !indicator lamp in the instru-
ment cluster is lit.
X To release: depress the brake pedal and
keep it depressed.
The selector lever lock is released.
X Pull parking brake ;up firmly.
X Press release button :on parking
brake ;and move parking brake ;down
to the stop.
The ! indicator lamp in the instrument
cluster goes out.
i If you pull away with parking brake ;
applied, a warning tone sounds. Parking up the vehicle
If you leave the vehicle parked up for longer
than four weeks, the battery may be damaged
by exhaustive discharging.
X Disconnect the battery.
or
X Connect the battery to a trickle charger.
i You can obtain information about trickle
chargers from a qualified specialist work-
shop.
If you leave the vehicle parked up for longer
than six weeks, the vehicle may suffer dam-
age as a result of lack of use.
X Visit a qualified specialist workshop and
seek advice. Driving tips
Short journeys
! Vehicles with adiesel particle filter: if
the vehicle is mostly driven for short dis-
tances, it is possible that malfunctions may
occur during the automatic cleaning of the
diesel particle filter. This may lead to fuel
collecting in the engine oil and cause
engine failure. Therefore, if you frequently 164
Driving tipsDriving and parking

drive short distances, you should take a 20
minute trip on a motorway or rural road at
least every 500km. Brakes
Important safety notes G
WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
This increases the risk of skidding and having
an accident.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients On long and steep downhill gradients, espe-
cially if the vehicle is laden or towing a trailer,
you must select shift range
1,2or 3
(Y page 153) in good time.
i This also applies if you have activated
cruise control or SPEEDTRONIC.
This will use the braking effec tofthe engine,
so less braking will be required to prevent the
vehicle from gaining speed. This relieves the
load on the brake system and prevents the
brakes from overheating and wearing too
quickly. If you need additional braking,
depress the brake pedal repeatedly rather
than continuously.
Heavy and light loads G
WARNING
The braking system can overheat if you leave
your foot on the brake pedal while driving.
This increases the braking distance and could
even cause the braking system to fail. There
is a risk of an accident.
Never use the brake pedal as a footrest.Do
not simultaneously depress both the brake
pedal and the accelerato rpedal while driving. If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short while. This allows the air-
flow to cool the brakes more quickly.
If the brakes have been used only moderately,
you should occasionally test their effective-
ness. To do this, brake more firmly from a
higher speed. This improves the grip of the
brakes.
Wet road surfaces
If driving in heavy rain for a prolonged period
of time without braking, there may be a
delayed reaction from the brakes when brak-
ing for the first time. This may also occur after
the vehicle has been washed.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehi-
cle washed, brake firmly while paying atten-
tion to the traffic conditions .This will warm
up the brake discs, thereby drying them more
quickly and protecting them against corro-
sion.
Limited braking performance on salt-
treated roads If you drive on salt-treated roads, a layer of
salt may form on the brake discs and pads.
This can increase the braking distance con-
siderably.
R
Apply the brakes occasionally in order to
prevent any salt build-up. Ensure that you
do not endanger other road users when
doing so.
R Carefully depress the brake pedal at the
end of the journey and when starting the
next journey.
R Maintain a much greater distance to the
vehicle in front. Driving tips
165Driving and parking Z

Driving on wet roads
Aquaplaning If water has accumulated to a certain depth
on the road surface, there is a danger of aqua-
planing occurring, eve nif:
R you are driving at low speeds
R the tyres have adequate tread depth.
For this reason, do not drive in tyre ruts, and
brake carefully.
Driving on flooded roads !
Bear in mind that vehicles travelling in
front or in the opposite direction create
waves. This may cause the maximu mper-
missible water depth to be exceeded.
These notes must be observed under all
circumstances. You could otherwise dam-
age the engine, the electronics or the trans-
mission.
If you have to drive on stretches of road on
which water has collected, please bear in
mind that:
R the maximum permissible fording depth in
still water is 60 cm
R you should drive no faster than walking
pace
Off-road fording !
The water depth must not exceed 60 cm.
Note that the possible fording depth is less
in flowing water.
! Under no circumstances should you
accelerate before entering the water. The
bow wave could cause water to enter and
damage the engine and neighbouring
assemblies.
! Do not open any of the vehicle's doors
while fording. Otherwise, water could get
into the vehicle interior and damage the
vehicle's electronics and interior equip-
ment. The fording depth must not exceed 60 cm
when the vehicle is loaded and ready to drive.
Loaded and ready to drive means: a full tank,
all fluids topped up and the driver is in the
vehicle.
i
You may only drive through freshwater.
R Observe the safety notes (Y page 169)and
the general notes (Y page 169) on off-road
driving.
R Establish how deep the water is and the
characteristics of the body of water before
fording.
R Switch off the air-conditioning system.
R Deactivate the auxiliary heating.
R Shift the transfer case to LOW
RANGE( Ypage 201).
R Engage the differential locks, if necessary
(Y page 204).
R Restrict the shift range to 1or
2(Y page 153).
R Avoid high engine speeds.
R Enter and exi tthe water at a flat place and
at a steady walking pace.
R Drive slowly and at a constant speed
through the water.
R Do not stop and do not switch off the
engine.
R Water offers a high degree of resistance,
the ground is slippery and, in some cases,
unstable. Therefore, it is difficult and dan-
gerous to pull away in the water.
R Ensure that a bow wave does not form as
you drive. Driving tips
167Driving and parking Z

R
Clean any mud from the tyre tread after
fording.
R Apply the brakes to dry them after fording.
R Water offers a high degree of resistance,
the ground is slippery and ,insome cases,
unstable. Therefore, it is difficult and dan-
gerous to pull away in the water.
R Ensure that a bow wave does not form as
you drive.
R Clean any mud from the tyre tread after
fording.
R Apply the brakes to dry them after fording. Parking the vehicle after heavy loads
on the engine
! Vehicles with adiesel engine: your
vehicle's exhaust gas turbocharger may get
very hot under heavy engine load, e.g. dur-
ing:
R trailer towing
R longe rmotorway journeys at high speed
R longer journeys through mountainous
terrain
X Let the engine run for approximately
another two minutes while the vehicle is
stationary before switching off the engine.
This way, the exhaust gas turbocharger can
cool down more effectively. Winter driving
General notes G
DANGER
If the exhaust pipe is blocked or adequate
ventilation is not possible, poisonous gases
such as carbon monoxide (CO) may enter the
vehicle. This is the case, e.g. if the vehicle
becomes trapped in snow. There is a risk of
fatal injury.
If you leave the engine or the auxiliary heating
running, make sure the exhaust pipe and area
around the vehicle are clear of snow. To ensure an adequate supply of fresh air, open
a window on the side of the vehicle that is not
facing into the wind. G
WARNING
If you have fitted snow chains to the front
wheels, they may scrape against the vehicle
body or chassis components. This could
cause damage to the vehicle or the tyres.
There is a risk of an accident.
To avoid hazardous situations:
R never fit snow chains on the front wheels
R fit snow chains to the rear wheels in pairs.
At the onset of winter, have your vehicle win-
terproofed at a qualified specialist workshop.
Observe the notes in the "Winter operation"
section (Y page 323).
Driving with summer tyres Observe the notes in the "Winter operation"
section (Y
page 323).
Slippery road surfaces G
WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
This increases the risk of skidding and having
an accident.
Do not shift down for additional engine brak-
ing on a slippery road surface.
You should drive particularly carefully on slip-
pery road surfaces. Avoid sudden accelera-
tion, steering and braking manoeuvres.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X Move the transmission to position N.
X Try to bring the vehicle under control by
using corrective steering.
i For more information on driving with
snow chains, see (Y page 324).168
Driving tipsDriving and parking

R
Chec kthat items of luggage and loads are
stowed safely and are well secured
(Y page 271).
R To avoid damaging the vehicle, make sure
there is always sufficient ground clearance.
R Always keep the engine running and in gear
when driving on a downhill gradient.
R Always keep the engine running and in gear
when driving on a slope.
R Drive slowly and evenly, if necessary at
walking pace.
R Ensure that the wheels are in contact with
the ground at all times.
R Drive with extreme care on unknown off-
road routes where visibility is poor. For
safety reasons, get out of the vehicle first
and survey the off-road route.
R Check the depth of water before fording
rivers and streams.
R When fording, do not stop and do not
switch off the engine.
R Look out for obstacles such as rocks, holes,
tree stumps and furrows.
R Always keep the doors, the rear door or
tailgate (G-Class Cabriolet), the side win-
dows and the sliding sunroof closed while
the vehicle is in motion.
R Switch off cruise control and variable
SPEEDTRONIC.
R Do not stray from marked routes or paths.
R Adapt your speed to the terrain. The
rougher, steeper or more ruts on the ter-
rain, the slower your speed should be.
R Drive slowly and at a constant speed
through the water. Ensure that a bow wave
does not form as you drive.
R On sand, drive quickly to overcome the roll-
ing resistance. Otherwise, the vehicle could
dig itself into the sand.
R Do not jump with the vehicle as this will
interrupt the vehicle's propulsion. R
Avoid high engine speeds. Drive at appro-
priate engine speeds.
R Always check the vehicle for damage after
off-road driving.
i Information about retrofitting special all-
terrain tyres is available from any qualified
specialist workshop.
i Do not use the HOLD function when driv-
ing off-road, on steep uphill or downhill gra-
dients or on slippery or loose surfaces. The
HOLD function cannot hold the vehicle on
such surfaces.
Checklist before driving off-road !
If the engine oil warning lamp lights up
during the journey, stop the vehicle in a
safe place as soon as is possible. Check the
engine oil level. The warning given by the
engine oil warning light must not be
ignored. Continuing your journey when the
symbol is shown may result in engine dam-
age.
X Engine oil level: check the engine oil and
top it up if necessary.
Only then does the engine receive enough
oil when the vehicle is standing on a steep
incline.
X G3 50 BlueTEC: have the AdBlue ®
level
checked at a qualified specialist workshop
(Y page 160).
X Tyre-change tool kit: check that the jack
is working and make sure you have the
wheelbrace, a robust tow cable and a fold-
ing spade in the vehicle.
X Wheels and tyres: check the tyre tread
depth and tyre pressure.
X Check for damage and remove any foreign
objects, e.g. small stones, from the
wheels/tyres.
X Replace any missing valve caps.
X Replace dented or damaged wheels.
X Carry a sound spare wheel. 170
Driving tipsDriving and parking