George,
What you've written makes sense, as you concluded.... but is based on
disregarding one important fact; there are two kinds of thermostatic radiator
caps: the kind that only burps, and the other kind that burps and gulps. What a
difference a hiccup can make!
Jim
Gonaj@aol.com wrote:
> All of the caps that I recall have a spring between the top of the cap and
> the seal which mates with a flange inside of the filler opening. This flange
> (seal) is below the overflow and prevents coolant overflow until the pressure
> of the system, as calculated for temp., exceeds it's set point.
>
> In order for the system to be bi-directional the spring must be a bimetallic
> so that it will operate like a thermostat. All systems must be
> bi-directional regardless of weather they were originally equipped with an
> overflow tank or not. If they were not bi-directional there could be enough
> vacuum created as to crush the thin walls of the radiator tubing.
>
> Now I will grant you that I am sitting in isolation at 3:30 AM theorizing as
> to the physics of what is happening but I am confident as to my conclusion.
> FWIW
>
> George
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