Cooling system
Overview
The cooling system cools the en-
gine in order to maintain a proper
operating temperature and prevent
overheating. On some engines, the
cooling system also cools the fuel,
the oil or the intake air. The cooling
system is made of two circuits:
• The
COOLANT CIRCUIT
which
is the engine’s internal cooling
system. It’s a closed-circuit in
which coolant flows and cools the
engine.
• The
RAW WATER CIRCUIT
which cools the coolant via heat
exchange with raw water. Nanni
engines comes as standard with
an heat exchanger, in which
the coolant is cooled by heat
exchange with raw water taken
from a sea cock. A Keel Cooling
system can also be used to cool
the coolant instead.
A thermostat maintains the coolant
at a proper and constant operating
temperature. With thermostat con-
trol, the coolant only enter the heat
exchanger when the engine reach
a certain temperature.
I
CAUTION
Operating the engine without
coolant or raw water supply,
even for few seconds, will lead to
complete engine failure.
Operation principle of
the cooling system
Operation principle of an engine
with heat exchanger:
Engine
Recovery tank (if fi tted)
Coolant pump
Thermostat
Heat exchanger
Exhaust elbow
Engine raw
water pump
Raw water
fi lter
Raw water
pickup
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