when the ac charge is low cyclng of the clutch occurs.This sort of prevents damage to the compressor. more importantly though is to find out out where the leak occurs. You can do a visual test to see if any of the lines especially by couplings to see evidence of refrigerant oil. If it is not evident I suggest adding some oil to the system then charge with freon , better yet with a dye.A/C work can be tricky and complex since there are so many areas and steps to to do to have a reliable system. I replaced my compressor last year and i had a leak at one of the couplings at the accumulator . I evacuated the system after changing the accumulator , this week as a matter of fact , just to find out that I had a leak elsewhere. Turns out that the low pressure hose which runs from the passenger side to the drivers side where the compressor is located had a hole in caused by the high pressure hose contacting it and over time causing a hole . luckily I was able to source a replacement from eeuroparts for under $50. It is sceduled to arrive soon .Good luck