2012 MERCEDES-BENZ G-CLASS SUV overheating

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

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

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

be warned visually and acoustically. DIS-
TRONIC PLUS cannot preven tacollision with-
out your intervention. An intermittent warn-
ing tone will then sound and the distance
warning lamp will light up in the instrument
cluster. Brake immediately in order to
increase the distance from the vehicle in
front, or take evasive action, provided it is
safe to do so.
DISTRONIC PLUS may not detect narrow
vehicles driving in front, e.g. motorcycles, or
vehicles driving on a different line. Therefore,
always pay attention to traffic conditions
even when DISTRONIC PLUS is activated.
Otherwise, you may fail to recognise dangers
in time, cause an accident and injure yourself
and others.
If DISTRONIC PLUS is activated, the vehicle
brakes automatically in certain situations.
This can happe nunexpectedly, especially
when towing or in a car wash. There is a risk
of an accident. In these or similar situations,
deactivate DISTRONIC PLUS.
If you want DISTRONIC PLUS to assist you,
the following activatio nconditions must be
fulfilled (Y page 184) and the radar sensor
system must be operational.
General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. DIS-
TRONIC PLUS brakes automatically so that
the set speed is not exceeded.
On long and steep downhill gradients, espe-
cially 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 DISTRONIC PLUS detects a slower-moving
vehicle in front, your vehicle is braked in order
to maintain the preset distance to the vehicle
in front. If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control in the speed range between
30 km/ha
nd 200 km/h. If avehicle is driving
in front of you, DISTRONIC operates in the
speed range between 0km/h and
200 km/h.
Do not use DISTRONIC PLUS on roads with
steep gradients.
Cruise control lever :
To activate or increase speed
; To set the specified minimu mdistance
= LIM indicator lamp
? To activate at the current speed/last
stored speed
A To activate or reduce speed
B To switch between DISTRONIC PLUS and
variable SPEEDTRONIC
C To deactivate DISTRONIC PLUS
With the cruise control lever, you can operate
DISTRONIC PLUS and variable SPEED-
TRONIC.
X To switch between variable SPEED-
TRONIC and DISTRONIC PLUS: press the Driving systems
183Driving and parking Z

for a maximu
mload; see the tyre pressure
table in the fuel filler flap (Y page 325).
You will find installation dimensions and loads
in the technical data (Y page 350).
The maximum permissible trailer drawbar
noseweight on the ball coupling is:
R 140 kg (G-Class long-wheelbase version)
R 115 kg (G-Class Cabriolet)
However, the actual noseweight must not
exceed the value given on the trailer tow hitch
or trailer identification plates. The lowest
weight applies.
i When towing a trailer, set the tyre pres-
sure on the rear axle of the towing vehicle
for a maximum load; see the tyre pressure
table in the fuel filler flap (Y page 325).
Please note that when towing a trailer, PARK-
TRONIC (Y page 197) and Blind Spot Assist
(Y page 190) are only available with limita-
tions, or not at all.
i On vehicles without level control, the
height of the ball coupling will alter accord-
ing to the load placed on the vehicle. If nec-
essary, use a trailer with a height-adjusta-
ble drawbar.
Driving tips X
On long and steep downhill gradients,
select shift range 1,2or 3(Y page 153) in
good time.
i This also applies if you have activated
cruise control or SPEEDTRONIC.
X If necessary, shift the transfer case to LOW
RANGE(Y page 202).
This will use the braking effect of the
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 addi-
tional braking, depress the brake pedal
repeatedly rather than continuously. The maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check
the trailer's documents to see what the max-
imum permitted speed is. Observe the legally
prescribed maximum speed in the relevant
country.
For certain Mercedes-Benz vehicles, the max-
imum permissible rear axle load is increased
when towing a trailer. Refer to the "Technical
data" section to find out whether this applies
to your vehicle. If you utilise any of the added
maximum rear axle load when towing a trailer,
the vehicle/trailer combination may not
exceed a maximum speed of 100 km/h for
reasons concerning the operating permit.
This also applies in countries in which the
permissible maximum speed for vehicle/
trailer combinations is above 100 km/h.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
to when driving without a trailer, and it will
consume more fuel.
Driving tips
If the trailer swings from side to side:
X
Do not accelerate.
X Do not countersteer.
X Brake if necessary.
R Maintain a greater distance from the vehi-
cle in front than when driving without a
trailer.
R Avoid braking abruptly. If possible, brake
gently at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude. Towing
atrailer
207Driving an d parking Z

If the boiling point of the brake fluid is too low,
vapourp ockets may form in the brake system
when the brakes are applied hard (e.g. when
driving downhill). This impairs braking effi-
ciency.
You should have the brake fluid renewed at
regular intervals. The brake fluid change inter-
vals can be found in the Service Booklet.
Only use brake fluid approved by Mercedes-
Benz according to MB Approval 331.0.
Information about approved brake fluid can
be obtained at any qualified specialist work-
shop or on the Internet at:
http://bevo.mercedes-benz.com.
i Have the brake fluid regularly replaced at
a qualified specialist workshop. Coolant
Important safety notes G
WARNING
Antifreeze is highly flammable. Fire, naked
flames and smoking are prohibited when han-
dling antifreeze.
If antifreeze comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any antifreeze on hot
engine parts.
! Only add coolant that has been premixed
with the desired antifreez eprotection. You
could otherwise damage the engine.
Further information on coolants can be
found in the Mercedes-Benz Specifications
for Service Products, MB Specifications for
Service Products 310.1, e.g. on the Inter-
net at http://bevo.mercedes-benz.com.
Or contact a qualified specialist workshop.
! Always use a suitable coolant mixture,
even in countries where high temperatures
prevail. Otherwise, the engine cooling system is not
sufficiently protected from corrosion and
overheating.
! The engine cooling system is filled with
coolant, which must be renewed after
15 years or after 250,000 kilometres at the
latest.
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It performs the
following tasks:
R anti-corrosio nprotection
R antifreeze protection
R raising the boiling point
If antifreeze/corrosion inhibitor is present in
the correct concentration, the boiling point of
the coolant will be around 130 †.
The antifreeze/corrosion inhibitor concentra-
tion in the engine cooling system should:
R be at least 50%. This will protect the engine
cooling system against freezing downto
approximately -3 7†.
R not exceed 55% (antifreeze protection
down to -45 †). Hea twill otherwise not be
dissipated as effectively.
If the vehicle has lost coolant, top it up with
equal amounts of water and antifreeze/cor-
rosio ninhibitor. Mercedes-Benz recom-
mends an antifreeze/corrosion inhibito rin
accordance with MB Specifications for
Service Products 310.1.
The coolan tis checked at every maintenance
interval at a qualified specialist workshop.
i When the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures
adequate antifreeze and corrosion protec-
tion. Washer fluid
Important safety notes G
WARNING
Windscreen washer concentrate is highly
flammable. If it comes into contact with hot Service products and capacities
347Technical data
Z