be the evaporator corps but I would check a few les expansive alternatives first. # 1 check the pressure relief valve located on the manifold by the compressor i think a new one is like $10 form a majority of the venders. I have found some that will give off a slow leak over time. #2 is the expansion valve on the evaporator corps might be leaking. I think at this point your best bet is to pull the housing and check for UV die before throwing any more money at the problem. You might also want to see if your buddy's shop has a yellow jacket that can do an oil flush before you pull everything apart if there is a pin hole leak this will help force the die through it and will help you locate a leak. #3 pull the condenser and run some tech select a/c flush through it than blow it out with compressed air and see if you get any shavings. I never rule out the possibility that a compressor might have fraged the system at some time in the past. I hope this helps please let me know if you have any more questions I will do my best to help.
