65
S08 MAINTENANCE
COOLING SYSTEM
OVERVIEW
The cooling system cools the engine in order to maintain a
proper operating temperature and to prevent overheating.
On some engines, the cooling system also cools the fuel,
the oil or the air intake. The cooling system is built around
two circuits:
• The COOLANT CIRCUIT which is the engine internal
cooling system. It is a closed-circuit in which coolant
flows and cools the engine.
• The RAW WATER CIRCUIT which cools the coolant
via an heat exchange with raw water. Nanni engines
are delivered 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 con-
stant operating temperature. With thermostat control, the
coolant only enter the heat exchanger when the engine
reach the appropriate temperature of the engine.
Above picture: Principle of operation of water cooling with
heat exchanger on an engine.
External keel cooling principle
CAUTION !
Engines designed with an heat exchanger are not suitable
for a Keel Cooling system. Operating the engine without
coolant or raw water supply, even for few seconds, will
lead to a complete engine breakdown.
Instead of proper mix coolant, raw clean water can only
be used in case of emergency and for the shortest time
possible. As soon as back to shore, get in touch with
the nearest Nanni representative or seasoned marine
shipyard or workshop. Please refer to the Fluids section
for complete information.
• Always use coolant made of 50% antifreeze with
anticorrosion additive and 50% of clean water.
The antifreeze protects the engine against internal
corrosion.
• This mix must be used all year around, even if there is
no risk of frost.
• Never use water alone to completely fill the coolant
system.
Please refer to the Fluids section for complete
information.
To Next Page
Loading...
