Now that I have my 04 LS V8 back together after changing water pump, plastics (cross pipe, 9N499, Tstat housing). The degas bottle, radiator, dccv, and upper and lower hoses. No leaks!!! I have bled the system by the book and now if I have the heater on at 90 degrees, the car temp sits right at 207. If I turn the AC to 75, the car temp climbs to 220-225. I turn the heater back up to 90 and the temp goes back to 207. I have opened the bleed valve several times and don’t seem to get any more air out of the system. What am I doing wrong and/or what’s potentially broken?