39 Deluxe Coupe Stock Motor Losing Water

[Rooster in a Coupe]

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 30mins long and temps range from 100 degrees with full radiator, to 130/140 degrees after 3 or 4 trips and water level is somewhere below the top of the tubes. Have not taken it on any further trips without topping up, as I don't believe that the level should be that low.


There is little or no leaks in the cooling system
Compression and leak down tests OK
No evidence of oil in water
Motor not getting hot, max 140 degrees with water below top of tubes
No Tstats at this stage


Suspect partially blocked radiator. Restricted return through radiator means water pumps building pressure in top tank, causing water to blow out overflow


Intend to remove and clean radiator, flush block and install new hoses and Tstats
Thinking, clean radiator will improve flow, and Tstats will increase operating temp


I could be completely wrong about all of this, so if anyone out there could suggest any reason/cure
your help would be appreciated


Rooster in a Coupe