I've had this problem for some time now (I would say about 2 years), it only happens in summer. The temperatures where I live range between 105 and 118 degrees in summer. The car overheats when is idle with the A/C on after 20 or 25 min approximately. So far I already changed (all new):
- Radiator
- Fan,
- Installed an auxiliary fan
- Water pump (had a very small leak)
- Thermostat
- Upper hose (the lower hose is not bent so as to not to let the water flow )
- Thermostat housing (had a very small leak)
- A/C Condenser (it was very dirty, I thought it might be blocking the airflow)
- I burped it
- Checked the head gaskets (they are fine)