engine MERCEDES-BENZ G-CLASS SUV 2012 Repair Manual

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

Checklist after driving off-road
Driving ove
rrough terrain places greater
demands on your vehicle than driving on nor-
mal roads. After driving off-road, check the
vehicle. This allows you to detect damage
promptly and reduce the risk of an accident
to yourself and other road users.
X Shift the transfer case to HIGH
RANGE(Y page 202).
X Disengage the differential locks
(Y page 204).
X Clean the headlamps and rear lights and
check for damage.
X Clean the front and rear licence plates.
X Clean the wheels and tyres with a water jet
and remove any foreign objects.
X Clean the wheels, tyres, wheel arches and
the vehicle underside with a water jet;
check for any foreign objects and damage.
X Check whether twigs or other parts of
plants have become trapped. These
increase the risk of fire and can damage
fuel pipes, brake hoses or the rubber bel-
lows of the axle joints and propeller shafts.
X After the trip, examine without fail the
entire undercarriage, wheels, tyres, brakes,
bodywork structure, steering, chassis and
exhaust system for damage.
X After driving for extended periods across
sand, mud, gravel, water or in similarly dirty
conditions, have the brake discs, wheels,
brake pads/linings and axle joints checked
and cleaned.
X If you notice strong vibrations after off-road
driving, check for foreign objects in the
wheels and drive train and, if necessary,
remove them. Foreign objects can disturb
the balance and cause vibrations. Driving on sand Observe the following rules when driving on
sand:
R
Shift the transfer case to LOW
RANGE(Y page 202).
R Avoid high engine speeds.
R Limit the shift range of the automatic trans-
mission according to the off-road condi-
tions.
R Drive quickly to overcome the rolling resist-
ance. Otherwise, the vehicle could dig itself
into the sand.
R Drive in the tracks of other vehicles if pos-
sible. Make sure that the ruts are not too
deep, that the sand is firm enough and that
your vehicle has sufficient ground clear-
ance.
Tyre ruts and gravel roads !
Check that the ruts are not too deep and
that your vehicle has sufficient clearance.
Otherwise, your vehicle could be damaged
or bottom out and get stuck.
Observe the following rules when driving
along ruts in off-road terrain or on roads with
loose gravel:
R Shift the transfer case to LOW
RANGE(Y page 202).
R Avoid high engine speeds.
R Observe the safety notes (Y page 169) and
the general notes (Y page 169) on off-road
driving.
R Restrict the shift range of the automatic
transmission to 1(Ypage 153).
R Drive slowly.
R Where ruts are too deep, drive with the
wheels on one side on the middle section
of turf if possible.
Driving over obstacles !
Obstacles could damage the floor of the
vehicle or components of the chassis. Ask
passengers for guidance when driving over Driving tips
171Driving and parking Z

large obstacles. Any damage to the vehicle
always increases the risk of an accident.
! Drive with particular care when driving
over an obstacle while driving up or down
a steep slope.
The vehicle could otherwise tilt and slide
sideways or tip over. Observe the following rules when driving over
tree stumps, large stones and other obsta-
cles:
R
Observe the safety notes (Y page 169)and
the general notes (Y page 169) on off-road
driving.
R Shift the transfer case to LOW
RANGE( Ypage 202).
R Avoid high engine speeds.
R Restrict the shift range to 1(Ypage 153).
R Make sure tha tyou have enough ground
clearance before driving across an obsta-
cle.
R Drive very slowly.
R Try to drive straight over the centre of
obstacles: front wheel first, then rear
wheel. Travelling uphill
Approach/departure angle The table shows front approach/departure
angles
:and rear approach/departure
angles ;at maximum load. This information
only provides an indication. The respective
approach and departure angles vary accord-
ing to the vehicle tyres and optional equip-
ment. : ;
G-Class
long-wheel-
base ver-
sion
36° 27°
G 63 AMG
28° 31°
G 65 AMG
28° 31°
G-Class
Cabriolet
36° 27°
R
Observe the safety notes (Y page 169) and
the general notes (Y page 169) on off-road
driving.
R Follow the line of fall when driving on slopes
and steep inclines.
R Before driving on extreme uphill and down-
hill gradients, shift the transfer case to
LOW RANGE(Y page 202).
R Engage the differential locks, if necessary
(Y page 204).
R Drive slowly. 172
Driving tipsDriving and parking

R
Accelerate gently and make sure that the
wheels are gripping.
R Avoid high engine speeds, except when
driving on sandy and muddy routes with
high driving resistance.
R Whe ndriving downaslope, use the braking
power of the engine. Observe the engine
speed; do not overrev the engine.
R Select a shift range appropriate to the gra-
dient.
R Before tackling steep downhill gradients,
select shift range 1(Ypage 153).
R Always check the brakes after driving off-
road.
Maximum gradient-climbing capability On good road surfaces and with the
LOW
RANGE gear selected, the maximum gradi-
ent-climbing capability is 80%.
i If the load on the front axle is reduced
when pulling away on a steep uphill slope,
the front wheels have a tendency to spin.
4ETS recognises this and brakes the
wheels accordingly. The rear wheel torque
is increased and it is easier to pull away.
Hilltops When driving up an uphill gradient, slightly
reduce pressure on the accelerator immedi-
ately before reaching the brow of the hill.
Make use of the vehicle's own impetus to
travel over the brow.
This style of driving prevents:
R the vehicle from lifting off the ground on the
brow of a hill
R loss of traction
R the vehicle from travelling too quickly down
the other side.
Driving downhill R
Before tackling steep downhill gradients,
select shift range 1(Ypage 153). This way you use the engine's braking
effect to reduce the speed. If this is not
sufficient, brake gently. When doing so,
make sure that the vehicle is facing in the
direction of the line of fall.
R Observe the notes on driving in mountain-
ous terrain (Y page 173).
R Drive slowly.
R Do not drive at an angle down steep
inclines. Steer into the line of fall and drive
with the front wheels aligned straight. Oth-
erwise, the vehicle could slip sideways, tip
and overturn.
R Check that the brakes are working normally
after a long downhill stretch. Driving systems
Cruise control
Important safety notes G
WARNING
The brake pedal moves when cruise control
brakes the vehicle. Afoot in the area under
the brake pedal could become trapped. The
movement of the pedal, and therefore the
vehicle's ability to brake, may be restricted by
objects in the area under the brake. There is
a risk of an accident and injury.
Do not place your foot under the brake pedal.
Keep the area under the brake pedal free from
obstructions.
If you fail to adapt your driving style, cruise
control can neither reduce the risk of acci-
dent nor override the laws of physics. Cruise
control cannot take account of road, weather
and traffic conditions. Cruise control is only
an aid. You are responsible for the distance
to the vehicle in front, for vehicle speed and
for braking in good time. Adjust your driving
style to the traffic conditions. Only engage
cruise control when the current road, weather
and traffic conditions permit it to be done
safely. Drive carefully and maintain a suitable
distance to the vehicle in front. Driving systems
173Driving and parking Z

Do not use cruise control:
R
in traffi cconditions that do not allow you
to drive at a constant speed, e.g. heavy
traffic, on winding roads or off-road
R on slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid.
R when there is poor visibility, e.g. due to fog,
heavy rain or snow
General notes Cruise control maintains a constant road
speed for you. On long and steep downhill
gradients, especially if the vehicle is laden or
towing a trailer, you must select shift range
1,
2or 3in good time. By doing so, you will
make use of the braking effect of the engine.
This relieves the load on the brake system and
prevents the brakes from overheating and
wearing too quickly.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a
steady speed for a prolonged period. You can
store any road speed above 30 km/h.
Cruise control lever :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds.
If an AdBlue ®
display message is shown in the
multifunction display, you will no longer be
able to use the full range of cruise control
functions.
The full range of cruise control functions will
become available again once you confirm the
AdBlue ®
display message:
X Briefly press the V,U,&or
* button on the multifunction steering
wheel.
or
X Briefly press the reset button on the instru-
ment cluster.
The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control is
selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected.
Activation conditions To activate cruise control, all of the following
activation conditions must be fulfilled:
R
the parking brake must be released.
R you are driving faster than 30 km/h.
R ESP ®
must be switched on, but not inter-
vening.
R the transmission must be in position D.
R the cruise control function must be selec-
ted (Y page 175). 174
Driving systemsDriving and parking

Making adjustments in 10 km/h incre-
ments
:
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
X Briefly press the cruise control lever
up : or down ?to beyond the pressure
point.
The lasts tored speed increases or decrea-
ses in 10 km/h increments.
Deactivating cruise control :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed A
To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
There are several ways to deactivate cruise
control:
X Briefly press the cruise control lever for-
wards B.
or
X Brake.
or
X Briefly press the cruise control lever in the
directio nofarrowA.
Variable SPEEDTRONIC is selected. LIM
indicator lamp ;in the cruise control lever
lights up.
Cruise control is automatically deactivated if:
R you apply the parking brake.
R you are driving at less than 30 km/h.
R ESP ®
intervenes or you deactivate ESP ®
.
R you shift the transmission to position N
while driving.
R G3 50 BlueTEC: you engage a differential
lock.
i The last speed stored is cleared when you
switch off the engine. SPEEDTRONIC
Important safety notes 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.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads. 178
Driving systemsDriving and parking

If you fail to adapt yourd
riving style, SPEED-
TRONIC can neither reduce the risk of acci-
dent nor override the laws of physics. SPEED-
TRONIC cannot take account of road, weather
and traffic conditions. SPEEDTRONIC is only
an aid.Y ou are responsible for the distance
to the vehicle in front, for vehicle speed, for
braking in good time and for staying in lane.
Only engage SPEEDTRONIC when the current
road, weather and traffic conditions permit it
to be done safely. Drive carefully and main-
tain a suitable distance to the vehicle in front.
General notes SPEEDTRONIC brakes automatically so that
you do not exceed the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer, you must
select shift range 1,2or 3in good time. By
doing so, you will make use of the braking
effect of the engine. 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 continu-
ously.
i The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Cruise control lever :
To store the current speed or a higher
speed
; LIM indicator lamp
= To call up the last speed stored ?
To store the current speed or a lower
speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate variable SPEEDTRONIC
You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.
The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control is
selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected.
You can use the cruise control lever to limit
the speed to any speed above 30 km/hw hile
the engine is running.
Selecting variable SPEEDTRONIC :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
If you fail to adapt your driving style, SPEED-
TRONIC can neither reduce the risk of acci-
dent nor override the laws of physics. SPEED-
TRONIC cannot take account of road, weather
and traffic conditions. SPEEDTRONIC is only
an aid. You are responsible for the distance Driving systems
179Driving and parking Z