I have an a6 with the 2.8 and have bled my coolant system at the heater core at least twice a day for the last week, and every time it sits off for more than 20 minutes it has air back in the system. i have pressure tested it both hot and cold and have not found any leaks, however every time i start my car i have no heat until i bleed the system. every time i bleed the system i can hear the air coming through the bleeder on the heater core. how can it be retaining that much air? or how can i be gaining air while my car is off?
any help would be fantastic