ok,my 2 cents ,i have a 92 dakota that had a hose go bad ,so i bought a new hose and drier and expansion block,i bought some 134 compatible oil dumped some in by guesswork,didnt drain the old oil at all!,evac and charged with 134,works good,but it had a problem at idle it would push out some gas out of the pop off valve thats screwed in the back of the compressor,so come winter time i removed the valve and filled it with jb weld and put it back in,evac and charged the system,works fine,no leaks,this was at least 5 yrs ago,maybe more,compressor is somewhat noisy but was before i converted it,i was told by a mechanic at the time the compressor wasnt going to last very long?,as it and the truck has 348000 miles on it and still puttin out cold air
your experience may vary!1