Cooling System - Westerbeke 4.5 BCG Operator's Manual

COOLING SYSTEM
DESCRIPTION
Westerbeke marine engines are designed and equipped for
fresh water cooling. Heat produced in the engine by combus-
tion 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
th~
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 indepen-
dent of each other. Using only fresh water coolant within the
engine allows the cooling water passages to stay clean and
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 be easily accessible.
jTO COOLANT RECOVERY
TANK ·
COOLANT EXPANSION
KEEP THESE PASSAGES CLEAR TO ENSURE
A 'FULL FLOW OF COOLANT TO AND FROM
THE COOLANT RECOVERY TANK (A PIPE
CLEANER WORKS WELL)
free from harmful deposits. ,,..·--.._'-......_
ENGINE COOLING DIAGRAM (TYPICAL)
WATER ---.. - - - FIRESSURE CAP
INJECTED ELBOW - - - -
FRESH WATER¢
RAWWATER . . . .
MANIFOLD
·PRESSURE
CAP
INCOMING
RAW WATER
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 vplve.opens and
closes tightly. Carry a spare cap.
14
RAW WATER DRAIN