A few years ago, I got a leak somewhere in the A/C system, never bothered to troubleshoot it, I just went without A/C. Recently, the compressor has been rattling, it sounds as if the bearings are going. Not wanting to lose the serpentine belt, I picked up a compressor from the boneyard to put in, but before I stick it in: Does the 134a lubricate the compressor at all? I don't want to throw a new compressor in there and have it wear out prematurely.

 

Yes the 134a acts as an oil to compressor but if the compressor is not kicking on it might be the clutch pulley.