Volvo Penta D1-13 Workshop Manual page 46

20-0 Engine Information, General
6
5
3
1
2
P0007846
1 Raw water, inlet
2 Raw water filter
3 Raw water pump
4 Raw water, outlet
5 Coolant pump
6 Expansion tank
7 Heat exchanger / exhaust manifold
8 Thermostat
9 Open thermostat - circulation
10 Closed thermostat - circulation
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7
9
8
10
4
Group 26: Cooling System
The engine is fresh water cooled and has a sealed
cooling system with expansion tank. The system is
divided into two circuits.
In the inner circuit, the fresh freshwater system, cool-
ant is pumped around by a coolant pump, driven via
a drive belt from the crankshaft pulley.
The fresh water system works under pressure, thus
reducing the risk of boiling if the temperature becomes
high. If the pressure becomes higher than normal, a
pressure valve opens in the filler cap on the expansion
tank.
The coolant temperature is regulated by a thermostat.
When the engine is cold, a thermostat directs the
coolant round an internal circuit in the engine. When
operating temperature begins to be reached, the cool-
ant is progressively directed out through the entire
heat exchanger, where the surplus heat is removed.
In the outer circuit - the raw water system - raw water
flow is taken care of by a gear-wheel driven pump of
rubber impeller type.
The raw water system cools the engine heat
exchanger. Raw water is discharged together with the
exhaust gas, via a connection in the exhaust bend.
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