Description Of Systems; Cooling System - Rotax 912 UL Operator's Manual

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
pressure valve opens and the coolant will flow via a hose at atmospheric
pressure to the transparent overflow bottle (4). When cooling down, the
coolant will be sucked back into the cooling circuit.
◆ NOTE:
Readings are taken on measuring point of the hottest cylinder head, depend-
ing on engine installation.
Coolant, see Chapter 10.2.1).
2
Effectivity: 912 Serie
OM Edition 1 / Rev. 0
Coolant temperatures are measured by means of tempera-
ture probes installed in cylinder heads 2 and 3.
Ausgleichsgefäß / expansion tank
3
1
Kühler / radiator
BRP-Rotax
4
Überlaufgefäß /
overflow bottle
fig. 4
08111
page 9 - 1
Jan. 01/2007