Pilots Operating Handbook
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YL-MFG
Revision 7, Issue 1
4/6/2016
7.16 Cooling System
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 (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. Mould
Readings are taken on measuring point of the hottest cylinder head, depending on engine
installation. The temperature sensors are located in cylinder head 2 and 3.
Engine is equipped with Oil/Coolant heat exchanger.
