>> 1) The shop manual recommends a 160F thermostat for summer and a 190
for winter.
YUP.
>>2) A 160F thermostat starts to open at 160 and is fully open at 180.
A 195F starts to open at 195 and is completely open at 215. If you are
worried about a marginal cooling system which one would you choose,
160 or 195?
This has always puzzled me. The operation of the engine produces a finite
amount of heat. The cooling system of the engine dissipates a finite
amount of heat. The combination of the, in time, two results in a stable
point of equilibrated temperature. That is, engine temerature, wherever it
is measured, remains constant. It is the point at which heat generated
equals heat lost.
Now, suppose that temperature equilibrium is 185F. Then the 160F
thermostat is fully open. The temperature remains at 185F, since that is
the point at which heat generated equals heat lost. Now put the 190F
thermostat in. It doesn't open. Heat builds up, the 190F thermostat opens,
and cooling proceeds -- until temperature drops and the 190F thermostat
begins closing again. The engine can thus be made to run warmer with a
high-temp thermostat.
That is all fine and good. But the engine that runs too hot will not
benefit from the low temperature thermostat. If the equilibrium
temperature the of engine and cooling system is 215F, both the high-temp
thermostat and low-temp thermostat are fully open. And even though the
low-temp unit opens sooner, the system temperature will continue to rise
until reaching equilibrium temperature.
>>3) Changing a thermostat is the cheapest change you can make, less
than $5.00. If it doesn't work, put the 195 back in and you are not
out of too much $$$.
YUP. And if this works, I suspect the 195 was malfunctioning.
But hey! What do I know?
Eddy - B382002639
|