Hi, i had those exact same sympotms on my car, i managed to find that annoying screw today and bleed the system successfully (hopefully) and i am going to wait and see if the problem has resolved itself. My engine temperature seems fine and stable the only problem i have is when i fill the resevoir full of water it usually dissapears within a couple of days. Im working on a leak and i was wondering if it was normal when bleeding the system for bubbley water to come out of the pipe? Many thanks