Rotax OM-912, Operator'S Manual

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Effectivity: 912 Serie BRP-Rotax page 9 - 1
OM Edition 1 / Rev. 0 Jan.01/2007
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9) Description of systems
9.1) Cooling system
See fig. 4.
The cooling system of the ROTAX 912 is designed for liquid cooling of the
cylinder heads and ram-air cooling of the cylinders. The cooling system of
the cylinder heads is a closed circuit with an expansion tank.
The coolant flow is forced by a water pump, driven from the camshaft, from
the radiator to the cylinder heads. From the top of the cylinder heads the
coolant passes on to the expansion tank (
1 ). Since the standard location of
the radiator ( 2 ) is below engine level, the expansion tank located on top of
the engine allows for coolant expansion.
The expansion tank is closed by a pressure cap ( 3 ) (with excess pressure
valve and return valve). At temperature rise of the coolant the excess pres-
sure valve opens and the coolant will flow via a hose at atmospheric pres-
sure to the transparent overflow bottle (
4 ). When cooling down, the coolant
will be sucked back into the cooling circuit.
◆
NOTE: Coolant temperatures are measured by means of tem-
perature probes installed in cylinder heads 2 and 3.
Readings are taken on measuring point of the hottest cylinder head, depen-
ding on engine installation.
Coolant, see Chapter 10.2.1).
Überlaufgefäß /
overflow bottle
Kühler / radiator
Ausgleichsgefäß / expansion tank
08111
3
1
2
4
fig. 4