Wednesday, Jan 28, 2009 at 10:27
Here you go Shiralee....Confucius Say ..... Knowledge was never known to enter the head via an open mouth..
For your interest..oh and by simply living or working in the bush gives you no right to be rude.Image Could Not Be FoundImage Could Not Be FoundImage Could Not Be FoundImage Could Not Be FoundImage Could Not Be FoundImage Could Not Be Found
Use The Correct Thermostat
For today's engines to operate at maximum efficiency in terms of
performance, fuel economy and emission levels it is important for
the engine to get to the correct operating temperature as soon as
possible and ensure that temperature is maintained during all
operating conditions.
In order to do this manufacturers have redesigned their engines to
utilise what is called a reverse poppet or bypass style thermostat.
This style of thermostat has two valves instead of the one valve that
is seen on a non-bypass thermostat. The primary valve operates
exactly the same as the non-bypass thermostat and opens allowing
coolant to flow to the radiator when the engine is at normal operating
temperature. The secondary valve allows coolant to be circulated
back through the engine during its warmup stage. The temperature
of the engine is able to rise more evenly, minimising hot and cold
spots in the engine. The primary valve begins to open and the
secondary valve closes when the engine temperature rises. All
coolant is then directed through the primary valve to the radiator
ensuring that the correct operating temperature is maintained.
A vehicle fitted with a bypass style thermostat must always have
the correct bypass thermostat fitted. Vehicles fitted with non-bypass
thermostats must always be fitted with the correct non-bypass
thermostat. The fitting of an incorrect thermostat will cause the
engine to run differently to how it was designed. Overheating and
subsequent engine damage can be caused by using an incorrect
thermostat.
Correct Bypass Thermostat In
The Correct Application
Figure (1) shows the installation of the correct bypass style
thermostat. When the engine is cold the primary valve is closed
preventing the flow of coolant to the radiator. The secondary valve
is open and directs the flow of coolant back through the engine
allowing it to warm up faster. As the engine warms up the primary
valve begins to open and the secondary valve begins to close. Figure
(2) shows the secondary valve completely closed when the engine
is up to proper operating temperature. The primary valve is then
also completely open allowing full flow of coolant from the engine
to the radiator.
Incorrect Bypass Thermostat
In A Bypass Application
Figure (3) shows the use of an incorrect bypass thermostat in a
bypass application. If the secondary valve is incorrect it may not
close completely and coolant continues to flow through the bypass
port even though the primary valve is fully open. This will cause hot
coolant to return to the engine before it has been cooled. The engine
temperature will be hotter than required and may cause premature
failure of other components in the cooling system.
Non-Bypass Thermostat In A
Bypass Application
In this situation there is no secondary valve that will block off the
bypass port when the engine warms up (Figure 4). This will cause
hot coolant to continue to circulate through the engine without
going to the radiator. The engine will run hotter than required and
may cause a failure of other components in the cooling system.
Correct Non-Bypass Thermostat In
The Correct Application
In engines with no bypass port a non-bypass thermostat must be
used (Figure 5). No coolant flows until the thermostat opens. An
incorrect non-bypass thermostat used in these applications will
normally not physically fit or will be loose in the housing. Correct
opening temperatures must also be used.
Bypass Thermostat In A Non-Bypass
Thermostat Application
This is the worst possible combination as the secondary valve of
the thermostat will hit the bottom of the housing (Figure 6) and
prevent the thermostat from opening, as no coolant whatsoever
will circulate and the engine will overheat and boil. Major engine
damage may be caused as a result of this situation.
There is plenty of information on the net...I see you have access even being so remote and isolated in the bush, so you should have no touble researching about the NEED to restrict some flow in a non-bypass thermostat for effective cooling.
Finally... the origianl post was about fixing a cooling system to operate correctly...not a bush fix that will create more problems than it will solve.
All the best
Matt.
FollowupID:
614281