1986 bmw 528(e); 4 door; 2.7 6 cylin; 56,000 miles

Car ran hot on a 3 hour drive to New Orleans with a/c on and outside temp. about 102F. Temp. gauge hovered into red zone and I pulled over for a 1 hr cool off spell. Fan clutch and shroud were replaced one month ago after same problem. Limped back with a/c off and gauge was not in red zone.
Coolant in expansion tank was almost 2-3 inches above level (level when engine is cold).

Have a feeling car does not like hot weather. Any feedback on problem -especially if it is common to 528(e)'s would be appreciated.

Thank you