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AB Volvo Penta / Diesel Engine TAMD71B
10.2 Raw water pump
The raw water pump is fitted to the timing gear
cover at the front of the engine. This pump is
driven via the timing gears. The pump impeller is
made of rubber and can be replaced.
Note: The impeller may be damaged if the pump is run dry.
Fig. 10.5 Raw water pump
10.1 Thermostat
The engines have a piston thermostat which has
a bulb filled with wax. When the engine is cold,
the thermostat keeps the route to the heat ex-
changer completely closed. The coolant is then
fed directly back to the engine through a by-
pass line. After the engine has warmed up, the
volume of the wax increases and the thermostat
subsequently opens the route to the heat ex-
changer, while the by-pass line is closed.
Fig. 10.2 Coolant Pump (circulation pump) and
thermostat housing
1. Piston thermostat
Fig. 10.3 Thermostat function, cold engine
Fig. 10.4 Thermostat function at operating temperature
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