I recently did a drain and fill on my coolant for my car and I've noticed my HVAC system doesn't work as well as it used to. I've tried burping the system multiple times but the issue hasn't gone away. The driver side heat doesn't seem to work unless it's above 80F+ or MAX Heat. Also for some reason if I switch it to recirculate while there is heat coming from the driver side it starts to blow cold air. The passenger side doesn't have this issue at all, even when heat is coming out through both the passenger and driver side vents, the driver side is noticeably colder by about 2-3 degrees. Any insight on what the issue could be would be appreciated.