If you see ANYTHING in the sight glass,you stil have freon. The "bubbles" are more turbulence unless you have a pristine sight glass. It can be hard to determine. Another thing to be aware of is frreezing the core. This happens when you run the A/C with the fan on the lowest setting for extended...
:(You have to evacuate the refrigerant before disconnecting the the suction and discharge to remove the core. The r-12/r134a does not have an odor, even in high conc. The smell of coolant may indicate your heater valve is shot. Only about a 50$ part. Search the archives for posts on this. Make...