You can certainly heat the thermostat in water, monitoring temperature as the water heats, to check the temperature at which it opens and closes.  I would not drop it into boiling water, but rather put in in cold water and gradually raise the temperature with a thermometer in the water.  To do better, you would need to know the specs for opening time and opening width at various temperatures (if those things are features of the thermostat).  mcneely

---- Don Hanson <dhanson928@GMAIL.COM> wrote:
>    Is there an accepted method to test the function of one of our double
> style thermostats?   I am skeptical about the proper operation of my
> currently installed one.... lately....I have had some other issues with
> cooling and recently replaced my oil/coolant heat exchanger (mine had a pin
> hole water leak to the outside).   But I also noticed once recently that I
> could hear some bubbling in my coolant system when I shut the van off,  and
> I have not heard the fan recently.
>
>    Anyhow, I have a spare used thermostat sitting on my bench, unknown
> condition....I'd like to see if it actually works and maybe swap that
> in....If no worky, what kind or brand should I buy to get a good dependable
> part?
>
>    So can I drop the spare I want to test into boiling water and measure
> it, testing for function, or some such?   It would be good to know, even if
> I do just buy a replacement, that my spare is OK and working..
>    I have calipers  to measure mechanical things.

--
David McNeely