I mounted a recovery tank on my F3 and got it plumbed to the overflow tube, which was hidden from sight and access. I installed the Stant cap that is designed to work with recovery tanks (allows coolant to get sucked back into the radiator).

I topped off the radiator and fired her up. I drove it a half mile from where I store it to home. Because it was loosing coolant and the dash gauge indicated high temps, I wanted to measure the engine temp. I left it idling and measured the surface temperature of each head using an infrared non-contact thermometer at 10, 15, 20, 25 and 30 minutes. The ambient temp was 80 F. The driver's side temp was consistently and 160 F at each measurement and the passenger's side was 165 F. I interpreted these temps as good news.

At the 30 minutes, coolant started to drip off the frame onto the ground at a fairly quick rate. I cut the engine and started to look for the source. I check the recovery tank and found it to be dry. I thought that if my connection to the overflow tube was bad, some coolant would still reach the recovery tank. I ragged it all off and it stopped flowing. I fired it back up after having it off for about 15 minutes, and ran it for 20 more minutes. It would not leak again. I cut it off and searched some more. I found that the clamp on one of the lower radiator hoses (the one near the exit of the overflow tube) had some greenish white crust on it. I loosened the clamp to the point that it leaked, and the coolant dripped off the same points on the frame that it had previously. So, I tightened the clamp, and so far no more leaking.

I guess I took the long way to tightening a hose clamp.