I'm attaching photos of my AC compressor and the sticker where it was retrofitted to 134a refrigerant. Do I need to know anything special to replace the compressor? Do I need to replace the drier and orifice tube as well? I can get a new 4 seasons kit on rockauto for around $180 that has these 3 parts. The compressor says with R4 compressor and without switch. My system was retrofitted in 1998 and worked AMAZING up until a week ago. It gets warm then cold and cycles like that. Also the compressor has gotten insanely loud. It's been loud for a while but ever since it started acting weird it's gotten even louder. I'm attaching several pictures. Also, one more question. While my ac was working the compressor would constantly cycle on and off. I mean like every 30 seconds. Now, I could see this being low refrigerant, but the thing is that the compressor cycled on and off even when the AC was turned off. I mean the HVAC setting was in the completely off position. The blower would turn off, but the compressor would continue to cycle. To stop this I would have to unplug the compressor.