Radiator Cap

[Tom Cloud]

>> I'll probably get scalded for this one, but I think that removing the t-stat
>> actually can allow the water pump to cavitate, and possibly cause a pressure
>> difference between hot engine and cool (relatively) radiator which prevents
>> coolant from circulating.  While it may seem like I'm grasping for straws, I've
>> seen something like this in my work many times.
>
>I've read the opposite.  The idea was that the water circulated too 
>fast.  Apparently slower travelling water swirls and eddys around in 
>the radiator, allowing all the water to come into contact with the 
>tube surface.  When you remove the thermostat the water travels in a 
>more laminar fashion (because of the speed) and only part of the
>water contacts the tubing.  Any other ideas?

I can agree to both of the above -- that the pump may cavitate and
that the water could be laminar.  But, the laminar flow thing ....
think about that for a moment .... what are the odds, after making
all those bends and being stirred up by the pump, of the water
flowing so smoothly that only the "outside" of the flow gets cooled.
In fact, it'd seem that the slower water would be more likely to
be "laminar" than the fast .... to me anyway.

I'm still hardheaded and unconvinced .... I've seen engines "with"
restrictors get hot and I've run lots of vehicles without thermostats
and only experienced that they ran too cool!!!  The problem I've
experienced is with not using the pressure cap to force coolant into
all the areas of the engine (and possibly to prevent cavitation at
the pump -- a phenomenon which *does* occur).

Tom Cloud

   Warning, dates in calendar are closer than they appear !