If compressor assembly is being replaced, drain refrigerant oil from both defective compressor and new replacement compressor. Measure amount removed from defective compressor. If measured amount is less than 30 ml (1 fluid ounce), add 60 ml (2 fluid ounces) to new replacement compressor. If more than 30 ml (1 fluid ounce) is drained from defective compressor add same amount to new compressor. Use PAG refrigerant oil GM P/N 12345923 or equivalent.