Posted for "Al Gietzen" <alventures@email.msn.com>:

In an effort to design the most efficient coolant system possible,
I've
built my own header tank. I've drawn a diagram of the system similar to the
diagram provided by Lyn.

The only suggestion that I would make is that I think it best to have the
header tank connect to the inlet side on the pump because the major pressure
drop in the system is likely to be the rads.  That puts the pressure cap at
the lowest pressure point in the system.     To finish this tank I need to put a cap on it. I
searched the internet for aluminum filler necks and found some in England,
but while looking through my repair manual I found a pic of a bolt-on
plastic flange mount filler neck. This is shown in the pic "rad cap filler
neck". Can somebody out there tell me if this is just a mount for a filler
cap or if it is for a pressure cap? Can I also get the dimensions of it with
& without the cap.

Sure looks like a pressure cap to fitting to me.

Al Gietzen