Mercedes-Benz M-Class Owner's Manual page 295

Warning and indicator lamps in the instrument cluster
292
Problem
?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
Possible causes/consequences and M Solutions
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator
may be blocked or the electric engine radiator fan may be mal-
functioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
Observe the additional display messages in the multifunction
X
display.
Stop the vehicle immediately, paying attention to road and traf-
X
fic conditions, and switch off the engine.
Let the engine and coolant cool down.
X
Check the coolant level and top up the coolant (
X
Observe the warning notes as you do so.
If you have to top up the coolant frequently, have the engine
X
cooling system checked.
Make sure that the air supply to the engine radiator is not
X
blocked, e.g. by frozen slush.
If the coolant temperature is less than 120 †, you can continue
X
driving to the nearest qualified specialist workshop.
Avoid heavy loads on the engine as you do so, e.g. driving on
X
mountain roads and stop-start traffic.
The coolant temperature has exceeded 120 †. The airflow to the
engine radiator may be blocked or the coolant level may be too
low.
The engine is not being cooled sufficiently and may be damaged.
Observe the additional display messages in the multifunction
X
display.
Stop the vehicle immediately, paying attention to road and traf-
X
fic conditions, and switch off the engine.
Let the engine and coolant cool down.
X
Check the coolant level and top up the coolant (
X
Observe the warning notes as you do so.
If you have to top up the coolant frequently, have the engine
X
cooling system checked.
Make sure that the air supply to the engine radiator is not
X
blocked, e.g. by frozen slush.
If the coolant temperature is less than 120 †, you can continue
X
driving to the nearest qualified specialist workshop.
Avoid heavy loads on the engine as you do so, e.g. driving on
X
mountain roads and stop-start traffic.
page 321).
Y
page 321).
Y