Good article that I actually understood. I had an MGTD-sold it to get the money to elope-still have that wife and while I miss the car, she has turned out to have been a better investment.

While looking for some windshield wipers, I came across the bottle that I have in a parts list. It is called an expansion tank there and that plus the fact that it accepts a pressure cap is the final nail in the coffin. It all makes sense, so thanks again to all who responded.