2004 mustang overheated two times in a year. Replaced thermostat and flushed the radiator. It is my daughters car and I think the fan may not have come on the two times it overheated. The ac started blowing hot and she noticed temp was hot so shut the car off. After car cooled started the car and never got hot again for about a year then randomly did it again. Same result, cooled started and did not get hot. Any ideas are appreciated.