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RE: Hot TIgers

To: "Ed E. Powell" <102430.3640@compuserve.com>
Subject: RE: Hot TIgers
From: "Parlee, Brad (ED&C,SLS)" <brad.parlee@edc.ge.com>
Date: Mon, 8 Sep 1997 10:12:28 -0400
        The reason I go with the 160F thermostat is that my "equilibrium
state"  varies from 170F at highway speeds to meltdown at a stand still.
In Orlando Florida, where I do most of my driving in town or on country
lanes my speed varies across the full range and tends to come in chunks.
Thus I need the termal mass of the engine, water and radiator to smooth
out what's happening.  During a typical drive I'm Bombing along at 170F
and come to an unshaded intersection with a attractive hot dog vendor in
a bikini on the corner.  The pick up in front of me at the light tries
to take a turn (for hot dogs?) but gets his bassboat trailer jackknifed
in the process.  Since I was @ 170F I've got the 5 minutes to enjoy the
scenery and chuckle at the escapade while the boys work out there
problem.  At 200F I have to Jump the median or become part of the
debacle. So it depends on the environment you drive in.  In Florida
where its hot and we have hot dogs 160F gives us time to relax and
enjoy.

        I suspect the this thermal mass effect is why the manual
suggests 160F in the summer - buys a time cushion.
        .> 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 temperature,
> 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
> 

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