Supplement Airplane Maintenance Manual
Cessna 172 with TAE 125-02-99 / -114
AMM-20-02
Chapter:
Issue:
Issue Date:
Page:
Content:
20-AMM-71-02
3
06.11.2013
4
46
Rev. No:
Rev. Date:
1
25.08.2014
Then the engine parts are lubricated and cooled by the oil, the
turbocharger is supplied by an extra hose. The oil within the
engine is passing the bearings and then drops back into the
sump. The turbocharger oil is draining directly to the oil sump.
The measured values of oil temperature and pressure are
displayed at the CED 125 and led to the FADEC. The system
contains 4.5 to 6 liters oil, the level can be checked with the dip
stick.
Cooling system
The engine installation has got an independent liquid cooling
system, consisting of the following parts:
•
the radiator
•
the water pump
•
the thermostat
•
the heat exchanger
•
the expansion tank, including low level caution
•
the power plant as heat source and
•
lines and fittings
The installation uses a closed loop liquid cooling system with
external expansion tank and overflow bottle for engine cooling. In
normal operations a closed loop cooling system does not have
any loss of cooling fluid, the expansion tank ensures a proper
fluid level in various temperatures and pressure situations up to
the requested max. operation altitude of 18,000 ft. The three path
dual plate thermostat regulates the coolant flow between the
external and the short circuit. Below 84°C the short circuit is used
and the water pump is pushing the coolant back to the engine to
warm it up quickly. The heat exchanger for cabin heat is placed
behind the unregulated exit of the thermostat. According to
demand and outside air temperature the heat exchanger is
providing warm air to the cabin. At 84°C the thermostat starts to
open the path to the external circuit, the coolant is lead to the
radiator. At 94°C the path to the external is fully opened, the short
circuit is fully closed and the entire coolant is lead through the
radiator, which ensures a maximum temperature of 105°C. The
expansion tank is installed at the highest point of the cooling
system, the connections are leading from the expansion tank to
the water pipe, the coolant thermostat and the breather line to the
outside. A sensor within the tank is sending a signal to an amber
„Water Level“ caution lamp at the instrument panel.
Summary of Contents for Cessna 172
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