[Goat Boy]

^ +1
Pulling the expansion tank shouldn't get any air into the lower system but if for whatever reason if you did need to bleed it, there's a little twist plug hidden away at the top left hand corner of the rad (as seen when stood in front of the engine bay). It's a right PITA to get your fingers onto with enough grip to twist but loosening this (not removing) is the way to open the system when doing a big refill to bleed out any trapped air.