I recently purchased my IS. I noticed there was a whine at 1000 rpm with the ac on. Once I hit the ac button to turn off the ac the whine would go away. One day I was sitting in the car parked outside my house and the ac blew out hot air then started over heating.

Sounds like a bad AC compressor or Compressor clutch. I would also check the belt to make sure it's not worn or broken. Not sure what you mean by overheating...do you mean the engine or the air coming out became to hot?

The AC was blowing out cold then suddenly threw out hot/warmer air. Then the cars temperature starting getting hotter and hotter so I just shut it off so I wouldn’t hurt the engine. Before that my outside temperature was reading 111 when it was really 101. My belt was checked and it was fine.