Thermostat; Raw Water Cooling Pump - Westerbeke 8.0KW-60Hz ENDT Operator's Manual

COOLING SYSTEM
Refilling the Coolant
After replacing the engine block drain plug, close the heat
exchanger's coolant petcock. Then pour clean, premixed
coolant into the manifold and when the coolant is visable in
NOTE:
Open the air-bleed petcock on the thennostat housing.
Fill the system and watch for antifreeze coolant to flow from
the petcock then close the petcock.
Monitor the coolant in the manifold and add as needed. Fill
the
manifold to the filler neck and install the manifold pres-
sure 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.
TO COOLANT
RECOVERY TANK
MAKE CERTAIN THESE
PASSAGES ARE KEPT CLEAR
COOLANT RETRACTfON
NOTE:
Periodically check the condition of the rrulnifold 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.
THERMOSTAT
A thermostat, located near the manifold at the front of the
engine, controls the coolant temperature as the coolant contin-
uously flows through the closed cooling circuit. When the
engine is first started, the closed thermostat prevents 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 gas-
ket, 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.
COOLANT
TEMPERATURE
SWITCH
THERMOSTAT
ASSEMBLY
RAW WATER COOLING CIRCUIT
R BLEED
PETCOCK
THERMOSTAT
~COOlANT
TEMPERATURE
SENDOR
The raw water flow is created by a positive displacement
impeller pump. This pump draws water directly from the raw
water source (ocean, lake, or river) through a hose to the
water strainer. The raw water passes from the strainer
through the raw water pump to the heat exchanger (through
the heat exchanger tubes) where it cools the engine circulat-
ing fresh water coolant. The raw water is then discharged
into the water-injected exhaust elbow, mixing with and cool-
ing the exhaust gasses. This mixture of exhaust gas and raw
water is discharged overboard by the engine's exhaust gas
discharge pressure.
Raw Water Pump
The raw water pump is a self-priming, rotary pump with a
non-ferrous housing and a neoprene impeller. The impeller
has flexible vanes which wipe against a curved cam plate
within the impeller housing, producing the pumping action.
On no account should this pump be run dry as water acts as a
lubricant for the impeller. There should always be a spare
impeller and impeller cover gasket (an impeller kit) aboard.
Raw water pump impeller failures occur when lubricant (raw
water) is not present during engine operation. Such failures
are not warrantable, and operators are cautioned to make sure
raw water flow is present at start-up.
NOTE:
Should a failure occur with the pump
s
internal parts
(seals and bearings), it may be more cost efficient to pur-
chase a new pump and rebuild the original pump as a spare.
Engines
&
Generators
15