240 Checking and refilling levels
Coolant fluid loss
Any loss of coolant fluid normally indicates a leak in the cooling system. In
this case the cooling system should be inspected by a specialised work-
shop without delay. It is not sufficient merely to top up the coolant fluid.
If there are no leaks in the system, a loss of coolant fluid can only occur if
the coolant boils and is forced out of the system as a result of overheating.
CAUTION
Radiator sealants must not be added to the coolant fluid. Such additives
could seriously impair the function of the cooling system.
Topping up the coolant fluid
Be careful when topping up with coolant fluid.
–Switch the engine off.
–Wait for the engine to cool down.
–Cover the cap on the expansion tank ⇒ Fig. 182 with a cloth,
and carefully unscrew the cap anticlockwise ⇒ .
–Add coolant fluid.
–Screw on the cap tightly.
Make sure that the coolant fluid meets the required specifications
⇒ page 238. Do not use a different type of antifreeze if G12++antifreeze is
not available. In this case, use only water and bring the antifreeze concen-
tration back up to the correct level as soon as possible.
Always top up with new coolant fluid.
Do not fill above the “max” mark. Excess coolant fluid is forced out of the
system through the valve in the filler cap when the engine gets hot.
If a lot of coolant fluid has been lost, wait for the engine to cool down before
putting in cold coolant. Failure to do so could result in serious engine dam-
age.
WARNING
●The cooling system is under pressure. Do not unscrew the cap on the
expansion tank when the engine is hot. Failure to comply could result in
burns.
●The antifreeze and coolant fluid can be a health hazard. Therefore,
the antifreeze should be stored in the original container in a safe place
out of reach of children. Failure to comply could result in poisoning.
For the sake of the environment
Drained off coolant should not be used again. Drain off the used coolant in-
to a suitable container and dispose of it in the proper manner (observe envi-
ronmental regulations).
Radiator fan
The radiator fan can start running spontaneously.
The auxiliary fan can continue to run for as long as 10 minutes after stop-
ping the engine, even after the ignition is switched off. It may also start run-
ning suddenly ⇒ after some while if
●Stored heat raises the coolant temperature, or
●The hot engine compartment is additionally heated up by the sun.
