I flushed the radiator in my FD, and now the level always sits lower in the header tank/thermostat housing to where it used to. I can just see water at the bottom when I remove the filler cap, about 3 " or more down the neck. The AST always stays full. Is this normal? The odd thing is that before flushing the level used to sit at the small hose take off which carries air to the AST.
Since flushing, I have fixed some small leaks by replacing the top hose, all AST hoses, fitting an alumimium AST and changing both caps (again!). The system now holds pressure when hot and holds a small vacuum overnight when it cools - small release of vacuum as the caps are removed.
Keith