[Daddio]

I've gone thru 3 of these #@&% things!

The first was original, the second was a NOS which, as already mentioned, had 50 year old rubber seals in it and leaked within a couple years.

So I got one from a Tbird supplier and it's worked for a few years so far ......

Mine leaked coolant, but the vacuum diaphragms worked fine, so I can't see the sense in changing to a mechanical valve since the seals are probably the same.