Water Issues in a 31 Model A

[JonLedbetter]

My dad has a 1931 model A that is being stored at my house. The issue I am currently having is with losing water. I know the system is not pressurized, so my question is should I be losing water at the overflow tube under the cap? I am fairly new to the whole antique car thing. Is the cooling system suppose to recycle the water back through the car or am I just suppose to be adding water periodically since there is no coolant reservoir? I hope I'm not asking a stupid question, but any help would be greatly appreciated.