Volvo Penta 3.0GS/SX Owner's Manual page 51

Cooling system. Inhibiting
When laying up the boat for the winter it is important
that the cooling system be flushed with freshwater so
that deposits do not dry and to prevent the build-up of
salt crystals. Seawater in the system causes corrosi-
on when air is introduced and can cause the build-up
of salt crystals that could block the system. Flush
with clean freshwater. This work should be carried out
with the boat out of the water.
Flush the cooling system by removing the intake sea-
water suction hose (connected to the drive). Remove
hose at engine. Connect another hose of a suitable
length and put its other end into a bucket of freshwa-
ter. Keep the container filled. Remove the thermostat
and reinstall the thermostat housing.
Start the engine and let it idle for a few minutes. Stop
the engine.
IMPORTANT The pump must never run dry.
NOTE! Ensure that nobody is splashed with water
spraying out of the exhaust outlet.
To avoid corrosion in the coolant water ducts these
should be filled with either a 50/50 mixture of fres-
hwater and glycol, or emulsifying oil. Fill a bucket
with either the 50/50 mixture or the oil. If possible fix
up an overflow return to the bucket (or another buck-
et). Start the engine and let it idle. Stop the engine if
the bucket starts to empty and needs filling
IMPORTANT The pump must never run dry.
Start over. When the engine has been running for a
few minutes the entire cooling system will have been
flushed and filled with the mixture. A 50/50 mixture of
glycol and water will not need to be drained. If emul-
sifying oil is used, it must be drained if the tempera-
ture is likely to drop below freezing while the boat is
laid up.
IMPORTANT Emulsifying oil provides no anti-
freeze protection and must be drained if free-
zing temperatures are likely.
To drain see Cooling System. Draining
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