Re the two hole positions, see Service Bulletin subject no 2458 page 11 dated Sept. 15, 1939.
"Fig 2 illustrates the cross shaft adopted during 1933. In this cross shaft and all cross shafts used since then a hard and a soft pedal adjustment is provided"
Soft pedal top hole
Hard pedal bottom...
Had the same issue with my 39, blowing water out every time I took it out. Wasn't overfilled and not getting hot. Running stats. Eventually replaced radiator cap and haven't had to add coolant since. I can only suggest that the coolant is backing up in the header tank.
39 5 window Deluxe, got two screws in top edge and 5 clips spaced around the garnish. Found them troublesome to remove however with a bit of perseverance and a bit of skin it can be done
I know I need Tstats to increase temperature and slow the flow rate as suggested above.
I'm thinking 77yrs of crud build up causing restriction of flow in radiator and no Tstats to restrict water return to radiator, between these two I'm getting a head of water building in the top tank and what...
39 Deluxe Ford Coupe Stock Motor Losing Water (Non pressure system)
With a full radiator, there is water loss each time the car is used. Some of the water is blown out due to expansion, however, without topping up, each run thereafter results in more water being blown out. Trips are approx...