Ac unit outside heats up, you can hear noise, and fan stops working. When turned off for awhile it will restart. What is cause?

It needs repaired... Call your HVAC guy to come out and see if it can be saved. THe longer you wait the less likely it can be.

This is beyond a do-it-yourself job.

Could be as simple as a bad capacitor. They are inexpensive & easy to replace. Next most likely is a bad fan motor, more expensive & more difficult to replace. It gets worse from there on.