Cooling question

["Rick Ehlert" <ricke@idcnet.com>]

Since we were on the subject or radiators, I have a small question to ask:
My radiator cools GREAT!!  Even through the desert at continued high speed!
But here's the funny part: If I fill it when cold to the top, it will blow
it out the overflow tube everytime while driving!  (no overflow tank on it)
It seems to like to be 3/4 full!
Other than that, it never gives my any temp. problems...NEVER above 190
degrees.

Any idea what the deal is, list?

Thanks,
Rick Ehlert
Milwaukee
'65 MGB Mk 1