Al,

Yes! with everyone's input, it does now make sense, mind you I had seen that picture before and was somewhat confused with all the pipes going here and there, I could never understand what was going where.

One question Al, I thought the expansion bottle might need to be bigger as big as the overflow bottle shown - I guess your saying that it doesn't need to be that large as the overflow is taking up any further expansion.

George ( down under)

In my case the overflow bottle is the expansion tank.  The filler neck stays completely full of coolant.

I don’t know exactly how much total expansion there is; but I know that starting with about 3-4” in the bottom of the overflow bottle, no coolant goes overboard from there when the coolant temp is up to 220F, so the total is less than a quart.  At some point I will leave the cap off the overflow bottle and observe the change in the coolant level from cold to hot.

Al