Operating instructions
COOLING
SYSTEM
FRESH
WATER
COOLING
CIRCUIT
NOTE:
Refer
to
the
ENGINE COOLANT section for
the
recommended antifreeze and water mixture
to
be
used as
the
fresh water
coolant.
Fresh water coolant is pumped through the engine by a
circulating pump, absorbing heat from the engine. The
coolant then passes through the thermostat 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.When the engine is started cold, external coolant flow
is prevented 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 flow 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
significant loss
of
coolant and without introducing air into
the cooling system. This tank should be located at or above
the engine manifold level and should
be
ea~ily
accessible.
COOLANT
RECOVERY
TANK
NOTE:
Periodically
check
the
condition
of
the manifold pres-
sure
cap.
Ensure
that
the
upper and lower rubber seals
are
in
good condition and check that
the
vacuum
valve
opens and
closes
tightly.
Carry
a
spare
cap.
CHANGING
COOLANT
The engine's coolant must
be
changed according to the
MAINTENANCE
SCHEDULE.
If
the coolant is allowed to
become contaminated, it can lead to overheating problems.
A
CAUTION:
Proper
cooling
system
maintenance
is
critical;
a
substantial
number
of
engine
fai/ures
can
be
traced
back
to
cooling
system
co"osion.
Drain the engine coolant
by
removing the drain plug and
opening the manifold pressure cap. Flush the system with
fresh water, then reinstall the drain and start the refill process.
A
WARNING:
Beware
of
the
hot
engine
coolant.
Wear
protective
gloves.
Refilling
the
Coolant
After replacing the engine drain plug, open the air bleed
petcock
on
the exhaust manifold and slowly pour clean,
premixed coolant into the manifold.
Monitor the coolant in the manifold and add as needed. Fill
the manifold neck.
Once coolant begins flowing from the air
bleed petcock free
of
air bubbles, close the petcock and
install the manifold pressure cap.
Remove the cap on the coolant recovery tank and fill with
coolant mix to halfway between
LOW and
MAX
and replace
the cap. Run the engine and observe the coolant expansion
flow into the recovery tank.
Mter
checking for leaks, stop the engine and allow
it
to cool.
Coolant should draw back into the cooling system as the
engine cools down. Add coolant to the recovery tank
if
needed and check the coolant in the manifold. Clean up any
spilled
coolant.
,-
COOLANT
DRAIN
SEALS
LOCATED
JUST
BELOW
THE
INTAKE
MANIFOLD
CHECKING
THE
PRESSURE
CAP
FROM
COOLANT
RECOVERY
TANK
MAKE
CERTAIN
THESE
PASSAGES
ARE
KEPT
CLEAR
TO
COOLANT
RECOVERY
TANK
COOLANT
RETRACTION
Engines & Generators
13
COOLANT
EXPANSION