Installation manual

COOLING SYSTEM
DESCRIPTION
Westerbeke marine diesel engines 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, its internal
moving parts, and the engine oil. 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 transfern;Ci to the fresh water coolant
is conducted through the tubewail;,-t:o 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 clean and free from harmful deposits.
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 easily accessible.
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 failures can be
traced back to cooling system corrosion.
Drain the engine coolant by loosening the drain plug on the
engine block and opening
the manifold pressure cap. Flush
, the system with fresh water, then start the refill process.
NOTE: The drain petcock on the heat exchanger should also
be used to help drain engine coolant.
A WARNING: Beware of the hot engine coolant.
Wear protective gloves. /'
COOLANT-
DRAIN
• MANIFOLD/HEAT EXCHANGER
Refilling the Coolant
. After replacing the engine block drain plug, close the heat
exchanger'S coolant drain.
Then pour clean, premixed
coolant into the manifold and when the coolant is visable in
the manifold, start the engine and run it at slow idle.
NOTE: Open the air-bleed petcock on the thermostat housing.
When a steady flow
of coolant appears at the petcock, close
the petcock and fill the
system until the manifold remains full.
· Monitor the coolant in the manifold and add as needed. Fill
· the manifold to the filler neck 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.
After 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. Clean up any spilled coolant.
Engines & Generators
18