coolant temperature MERCEDES-BENZ M-Class 2014 W166 User Guide

Problem Possible causes/consequences and
0001 Solutions
000E
The red coolant
warning lamp comes on
while the engine is
running. The coolant level is too low.
!
Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
If the coolant level is correct, the airflow to the engine radiator
may be blocked or the electric engine radiator fan may be
malfunctioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
X Observe the additional display messages in the multifunction
display.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 179).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and add coolant, observing the warning
notes (Y page 367).
X If you need to add coolant more often than usual, have the
engine coolant system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X Do not start the engine again until the coolant temperature is
under 248 ‡(120 †). Otherwise, the engine could be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. 000E
The red coolant
warning lamp comes on
while the engine is
running. A warning tone
also sounds.
The coolant temperature has exceeded 248 ‡ (120 †). The
airflow to the engine radiator may be blocked or the coolant level
may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive whe nyour engine is overheated. This can cause some
fluids which may have leaked into the engine compartment to
catch fire.
Steam from the overheated engine can also cause serious burns
which can occur just by opening the hood.
There is a risk of injury. Warning and indicator lamps in the instrument cluster
327On-board computer and displays Z

Problem Possible causes/consequences and
0001 Solutions
X
Observe the additional display messages in the multifunction
display.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 179).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and add coolant, observing the warning
notes (Y page 367).
X If you need to add coolant more often than usual, have the
engine coolant system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X At coolant temperatures under 248 ‡(120 †), drive to the next
qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. Driving systems
Problem Possible causes/consequences and
0001 Solutions
000E
The red distance
warning function
warning lamp comes on
while the vehicle is
moving. A warning tone
also sounds.
You are approaching a vehicle or a stationary obstacle in you
rline
of travel at too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
Further information on DISTRONIC PLUS (Y page 194).
Further information on PRE-SAFE ®
Brake (Y page 74).
Further information on the distance warning function
(Y page 69). 328
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Example: engine oil cap
X
Turn cap 0002counter-clockwise and remove
it.
X Add engine oil.
If the oil level is at or below the MIN mark
on the oil dipstick, add 1.1 US qt (1.0 l) of
engine oil.
X Replace cap 0002on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level agai nwith the oil
dipstick (Y page 365).
Further information on engine oil
(Y page 448). Additional service products
Checking coolant level G
WARNING
Certain components in the engine
compartment, such as the engine, radiator
and parts of the exhaust system, can become
very hot .Working in the engine compartment
poses a risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following. G
WARNING
The engine cooling system is pressurized,
particularly when the engine is warm. When opening the cap, you could be scalded by hot
coolant spraying out. There is a risk of injury.
Let the engine cool down before opening the
cap. Wear eye and hand protection when
opening the cap. Open the cap slowly half a
turn to allow pressure to escape. X
Park the vehicle on a level surface.
Only check the coolant level when the
vehicle is on a level surface and the engine
has cooled down.
X Turn the SmartKey to position 2in the
ignition lock (Y page 157).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 158).
X Check the coolant temperature gauge in
the multifunction display.
The coolant temperature must be below
158 ‡ (70 †).
X Turn the SmartKey to position
0(Y page 157) in the ignition lock.
X Slowly turn cap 0002half a turn counter-
clockwise to allow excess pressure to
escape.
X Turn cap 0002further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
0023 in the filler neck when cold, there is
enough coolant in coolant expansion
tank 0003.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar 0023in the filler
neck when warm, there is enough coolant
in expansion tank 0003. Engine compartment
367Maintenance and care Z

Comply with the important safety notes for
service products when handlin
gbrake fluid
(Y page 444).
The brake fluid change intervals can be found
in the Maintenance 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
workshop or on the Internet at
http://bevo.mercedes-benz.com.
i Have the brake fluid regularly replaced at
a qualified specialist workshop and the
replacement confirmed in the Maintenance
Booklet. Coolant
Important safety notes G
WARNING
If antifreeze comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Let the engine cool down before you add
antifreeze. Make sure that antifreeze is not
spilled next to the filler neck. Thoroughly
clea nthe antifreeze from components before
starting the engine.
! Only add coolant that has been premixed
with the desired antifreezep rotection. 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
Internet 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.
i Have the coolant regularly replaced at a
qualified specialist workshop and the
replacement confirmed in the Maintenance
Booklet.
Comply with the important safety precautions
for service products when handling coolant
(Y page 444).
The coolant is a mixture of water and
antifreeze/corrosion inhibitor. It performs
the following tasks:
R corrosio nprotection
R antifreeze protection
R raising the boiling point
If the coolant has antifreeze protection down
to -35 ‡ (-37 †),the boiling point of the
coolant during operatio nis approximately
266 ‡ (130 †).
The antifreeze/corrosion inhibitor
concentration in the engine cooling system
should:
R be at least 50%. This will protect the engine
cooling system against freezing down to
approximately -35 ‡ (-37 †).
R not exceed 55% (antifreeze protection
down to -49 ‡ [-45 †]). Otherwise, heat
will not be dissipated as effectively.
If the vehicle has lost coolant, add equal
amounts of water and antifreeze/corrosion
inhibitor.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in
accordance with
MB Specifications for Service Products 310.1.
i When the vehicle is first delivered, it is
filled with a coolant mixture that ensures
adequate antifreeze and corrosion
protection.
i The coolant is checked with every
maintenance interval at a qualified
specialist workshop. 450
Service products and filling capacitiesTechnical data