I'm leaking coolant!

Not sure if this helps, but if I fill my radiator to the top, she will leak coolant out of the overflow tube when she is hot. I have since found that leaving the radiator just a little less filled has helped me retain my coolant, while still maintaining a safe operating temp. There are thin tube aftermarket coolant recovery bottles for sale that mount to the side of the radiator, and you run your tube into it to keep from losing coolant. I have not installed one of these yet, but am going to get to it one of these days.

P.S.

If your radiator is so low on coolant that it runs REAL hot, then your engine will have a pinging or ticking noise, very noticeable. You may have a clogged thermostat or collapsed lower radiator hose. Hope one of these helps you.

Dave

I may have the same problem as you but it only occurs when I drive the car really hard and then turn it off before I wind down my agressive driving.
I have a 65 gt-350 clone with 302 1974 block . I just purchased a 19" crome tube overflow 2" diameter by 19" length. it does not fit because the brackets are welded on to far apart . I have to exchange it for I think a shorter one maybe 16" . The brackets need to be 12" apart to fit properly. I will post the results in a few days.