too much cooling?

It's a good place to start

 

Probably not stuck open, more likely the return spring is just old & weak i.e. it will open up but then won't return as fast as far as it should. It will eventually close but very slowly & after the car has cooled down completely.

Just replace the Stat, that should solve the problem

I.

 

Also, check (or replace) the water temp sensor. My car "ran cool" until I replaced the sensor and now runs (typically) dead center.

Hope this helps.


Pietro

 

Before you start replacing parts, perhaps you could tell us if there have been any electrical issues in the history.
Has it always run at these temps or was there a sudden change/drop recently?

I tend to suspect the temperature sending units, gauges, and wiring connections. Please remember that these items are 1960's technology and not precision instruments.

Happy Holidays!

 

No the one located between spark plug 5 and 6 (towards the driver's side and the firewall). You shoud be able to replace it without draining the coolant (done when cold of course...). This gives you the temp reading and is not a switch -

Hope this helps -

Pietro