According to GM;
Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.
265 ml (9 fl. oz.) Polyalkaline Glycol (PAG) Refrigerant Oil for the 2.2L V7 Compressor
236 ml (8 fl. oz.) Polyalkaline Glycol (PAG) Refrigerant Oil for the 4.3L HT6 Compressor