Thermostat; Heat Exchanger - Westerbeke 8.0KW-60HZ Operator's Manual

COOLING SYSTEM
HEAT EXCHANGER
Cool raw water flows through the inner tubes of the heat
exchanger. As the engine coolant passes around these tubes
the heat of the internal engine is conducted to the raw water
which is then pumped into the exhaust system and discharged.
The engine coolant (now cooled) flows back through the engine
and the circuit repeats itself
The engine coolant and raw water are independent of each other,
this keeps the engine's water passages clean from the harmful
deposits found in raw water.
Heat Exchanger Service
After approximately 1000 hours of operation, remove, clean
and pressure test the engine's heat exchanger. (A local auto-
motive radiator shop should be able to clean and test the heat
exchanger. )
NOTE:
Operating in silty and/or tropical waters may require
that a heat exchanger cleaning be peiformed more often than
every 1000 hours.
ZINC ANODE _ _
~
HEAT EXCHANGER
SEALING O-RING
If the zinc anodes need replacement, hold the hex boss
into which the zinc anode is threaded with a wrench while
loosening the anode with another wrench. This prevents the
hex boss from possibly tearing off the exchanger shell. If the
zinc is in poor condition, there are probably a lot of zinc
flakes within the exchanger. Remove the end of the heat
exchanger and clean the inside of all zinc debris. Always
have a spare heat exchanger end gasket in case the present
one becomes damaged when removing the end cover.
Replace the gasket (refer to your engine model's heat
exchanger end gasket part number), O-ring and cover, and
install a new zinc anode.
NOTE:
The threads of the zinc anodes are pipe threads and
do not require sealant. Sealant should not be used as it
may insulate the zinc from the metal of the heat exchanger
housing preventing electrolysis action on the zinc.
THERMOSTAT
A thermostat, 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 thennostat 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 thennostat
gradually opens. The thermostat is accessible and can be
checked, cleaned, or replaced easily. Carry a spare thennostat
and gasket.
Replacing the Thermostat
To avoid spilling coolant, drain the coolant down below the
manifold level
(REFER TO CHANGlNG COOLANT).
COOLANT
Remove the cap screws and disassemble the thermostat
DRAIN
housing as shown. When installing the new thermostat and
gasket, apply a thin coat of sealant on both sides of the
CLEAR OUT
gasket before pressing it into place. Do
not
over-tighten the
ZINC DEBRIS
cap screws. Replace the coolant in the manifold. Run the
ZINC ANODE
engine and check for nonnal temperatures and that there are
~ zi~c ~o~e,
or pencil, is located in the raw water
c~oling ~
leaks
~l
the thermostat housing.
CIrcUIt wIthm the heat exchanger. The purpose of havmg - - .
zinc anodes is to sacrifice them to electrolysis action taking
place in the raw water cooling circuit, thereby reducing the
. effects of electrolysis on other components of the system. \
The condition of the zinc anode should be checked monthly
and the anode cleaned or replaced as required. Spare anodes .
should be carried on board.
NOTE:
Electrolysis action is the result of each particular
installation and vessel location; not that of If!e engine.
CLEAN & REUSE
aREPLACE
NEW
ZINC ANODES
Engines & Generators
15
GASKET
APPLY SEALANT
AT ASSEMBLY
THERMOSTAT
ASSEMBLY