I think you may be right about this. It seems to be the compressor cycling more than usual. I checked the 134a and it shows that its full.Is the compressor cycling on/off more often than normal? Did it cool like it used to? you could be low on refrigerant, causing the compressor on cycle more often, conseuentially low on pag oil. You could be noticing the how often the compressor cycles and not a louder clutch engagement?????