Pag Oil on the outside means less pag oil in the system. Now you dont know how much oil is left. Not enough oil will eventually be a problem for the compressor. Too much will degrade the cooling, etc..
Air left in the system will degrade performance. Air in the system mwans moisture is in there and that will eventually cause corosion and failure. If the gash let air in, probably the reciever drier can is saturated with moisture and that is also a problem.
Totally dry system is 10 ozs oil according to the dealer here.
It takes 2 full cans r134a, otherwise you get no cooling of the air.
Putting in stopleak is a problem, moisture inside the system may react with the sealer and clog the orfice tube, the compressor will hammer and can be ruined.
Fixing the pipe with epoxy or whatever is also a problem as it might not really hold and you are just wasting expensive r134a and your time.
I have found it a waste of time and money to try and take shortcuts with the AC.
The whole system needs to be flushed with a solvent, blown out with compressed air, a new drier installed, a new orfice tube, new O- rings on every connection, the bad pipe welded or replaced, 8 ozs. of 100 viscosity pag oil poured into the drier, the system has to vacuumed down to 29 inches and must hold for at least an hour.
I just got done fixing 2 of my cars and even had to replace leaky compressors. It is a lot, but unless you verify every part it is a waste of time.
