Installation manual
ENGINE
COOLING
CIRCUIT
DESCRIPTION
Westerbcke marine diesel generators are designed and
equipped
for fresh water cooling. Heat produced in the
engine
by combustion and friction is transferred to fresh
water coolant which circulates throughout the engine. This
circulating
fresh water coolant cools the engine block and its
internal moving parts.
The
heat is transferred externally from
the fresh water coolant to raw water
by means
of
a heat
exchanger, similar
in
function
to
an
automotive radiator.
Raw
water
flows through the tubes
of
the heat exchanger while
fresh
water
coolant flows around the tubes; engine heat trans-
ferred to the fresh water coolant
is
conducted through the
tube walls
to
the
raw
water which
is
then pumped into
the
exhaust
system where finally
it
is discharged overboard. In
other
words, the engine is cooled
by
fresh water coolant, this
coolant
is cooled by raw water, and the raw water carries the
transferred heat overboard through the exhaust system.
The
fresh
water
coolant and raw water circuits are independent
of
each
other. Using only fresh water coolant within the engine
allows
the cooling water passages to stay
dean
and free from
harmfu
I deposits.
Fresh
Water
Circuit
NOTE:
Refer to
ENGINE
COOLANT
sectiollfor the recom-
mended antifreeze and water mixture to be used as the fresh
water coo/alll.
Fresh water coolant
is
pumped
through the engine by a circu-
lating pump, absorhing heal from the engine.
The
coolant
then passes through the
themostat
into the manifold, to the
heat exchanger where
it
is cooled and returned to the
engine
block
via
the suction side
of
the circulating pump.
COOLANT
RECOVERY
TANK
ZINC
ANOOE---
DRAINS
TYPICAL
ENGINE
COOLING
CIRCUIT
llllllliI
When
the
engine
is started cold, external
coolant
flow is pre-
vented
by the
closed
thermostat
(although
some
coolant flow
is
bypassed
around
the thermostat to
prevent
the exhaust
manifold
from
overheating).
As
the
engine
warms
up, the
thermostat
gradually
opens,
allowing full flow
of
the
engine's
coolant
to
now
unrestricted to the external portion
of
the
cooling
system.
Coolant
Recovery
Tank
A
coolant
recovery
tank
allows for
engine
coolant
expansion
and
contraction
during
engine
operation,
without
any signifi-
cant
loss
of
coolant
and
without
introducing
air
into the
cool-
ing
system.
This
tank
should
be located at
or
above
the
engine
manifold level
and
should
he
easily
accessible.
CHANGING
COOLANT
The
engine's
coolant
must
be
changed
according
to the
MAINTENANCE SCHEDULE. If the
coolant
is allowed 10
become
contaminated,
it
can lead to
overheating
problems.
A
CAUTION:
Proper
cooling
system
maintenance
is
critical;
a substantial
number
of
engine
failures
can
be
traced
back
to
cooling
system
corrosion.
Drain
the
engine
coolant
by loosening the drain plug
on
the
engine
hlock and
opening
the manih)ld
pressure
cap. Flush
the
system
with fresh water, then start the refill process.
NOTE:
The drain pluf{ 011 the heat exchanger
call
also
be
used
to drain engine coolant.
A
WARNING:
Beware
of
the
hot
engine
coolant.
Wear
protective
gloves.
THERMOSTAT
HOUSING
RAW
WATER
IN
RAW
WATER
PUMP
32
KW
f
EXHAUST
~
WESTERBEKE
COOlANT
ยข
RAW
WATER
..
Engines & Generators
13