Regal 53 SC Owner's Manual page 218

Engine & Controls
COOLING SYSTEM
WARNING
!
TO AVOID PERSONAL INJURY DUE TO
HEATED COOLANT SPRAY OR STEAM,
DO NOT REMOVE THE PRESSURE CAP
FROM A HOT ENGINE. WAIT UNTIL THE
TEMPERATURE IS BELOW 50ºC 120ºF
HEAT EXCHANGER WITH EXPANSION TANK
CAP
General Information
The role of the cooling system is to maintain a specifi ed
operating temperature for the boat's engines. A portion
of the heat generated by the engine is absorbed by the en-
gine coolant fl owing through the passages in the cylinder
block and head. Heat is then removed from the engine
coolant as it fl ows through the heat exchanger.
As part of the cooling system the water pump is a belt-
driven, centrifugal-type pump with the inlet and bypass as
integral parts at the front of the engine.
If water pump replacement is needed, verify the correct
design type pump before installing a new one. The larg-
est difference is the drive pulley size. Using the incorrect
pump can cause decreased water fl ow and damage due to
oveheating conditions.
The thermostat controls the engine coolant temperature.
It is located at the engine front in the cylinder head. The
opening and closing of the thermostat is controlled by a
wax motor.
The thermostat features two vent holes to vent air past
the thermostat when it is closed. This is needed to fi ll the
cooling system.
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