Thermostat - Westerbeke 80N4 Operator's Manual

COOLING SYSTEM
Refilling the Coolant
After closing the engine block drain, pour clean, premixed
coolant into the manifold and when the coolant is visible in
the manifold, start the engine and run it at slow idle. Open
the air bleed petcocks on the manifold and the thermostat
housing.
Monitor the coolant in the manifold and add as needed. Fill
the manifold to the filler neck and when the coolant flowing
from the petcock is free of air bubbles, close the petcock and
install the 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. When the petcock on the
thermostat housing is free of air bubbles, close that petcock.
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. . /
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THERMOSTAT
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A thennostat, located near the manifold at the front of the
engine, controls the coolant temperature as the coolant
continuously flows through the closed cooling circuit.
When the engine is first started, the closed thermostat pre-
vents coolant from flowing (some coolant is by-passed
through a hole in the thermostat to prevent the exhaust
manifold from overheating). As the engine warms up, the
thermostat gradually opens. The thermostat is accessible
and can be checked, cleaned, or replaced easily. Carry a
spare thermostat and gasket.
Replacing the Thermostat
Remove the cap screws and disassemble the thermostat hous-
ing as shown. When installing the new thermostat and gasket,
apply a thin coat of sealant on both sides of the gasket before
pressing it into place. Do not over-tighten the cap screws.
Run the engine and check for normal temperatures and that
there are no leaks at the thermostat housing.
THE GASKET IS GROOVED
FITS AROUND THE OUTER
EDGE OF THE THERMOSTAT
CHANGING THE THERMOSTAT
TEMPERATURE
Engines & Generators
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