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7.2) Cooling system
System Overview
Coolant flow
Expansion tank
3
Effectivity: 912 Series
Rev. 1
The cooling system of the engine 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. Since the standard location of the radiator is below engine
level, the expansion tank located on the top of the engine allows
for coolant expansion.
From the expansion tank the coolant is sucked back to the
water pump. In common installations the coolant passes a radi-
ator in between. Additionally the expansion tank is closed by a
pressure cap (with excess pressure valve and return valve). At
temperature rise of the coolant the excess pressure valve
opens and the coolant will escape via hose at atmospheric
pressure. In common installation this hose is connected to an
overflow bottle. This overflow bottle allows the coolant to be
sucked back into the cooling circuit as the engine is cooling
down.
NOTE
The coolant temperature sensors are located in cylinder head 2
and 3.
1
Figure 4: Cooling system (symbolic)
Expansion tank
1
3
Radiator
BRP-Rotax
2
Pressure cap
2
4
Overflow bottle
4
09152
Page 7-5
Ed.4/January 01 2023
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