Another overheating situation 63 Slant six

The oil is fine, no foaming and minor discoloration, time for an oil change soon. I topped the radiator back with fluid and squeezed the bottom hose and yes there is movement and bubbles there but how accurate is that of a test?
The water at the bottom when I drained it was really cool, now warmth and the upper was quite hot.
Any more suggestions bar just replacing the radiator? So close to wits end!