I recently replaced the compressor, expansion valve and evaporator and recharged my system with Freeze 12. The compressor tends to cycle often and the system makes a howling noise when accelerating and decelerating. It does make cold air. If I bypass the pressure switch the compressor will run continuously leading me to think there's plenty of freon in the system. I sprayed soapy water over the connections and don't have any leaks. Any ideas?

 

Take it to a shop. You cant DIY AC work.

Did you use oil when you redid the system? What oil? How much? Where was it placed? Did you flush the system? Did you charge the correct weight of refrigerant? Did you change the dryer? Did you vacuum the system? How long? Did it hold?

These are all things that MUST be done with AC repair. There is no way it will work if you don't, and all you will do is grenade the compressor (which I assume is used, which also won't work).