Air Conditioning System Precautions: Compressor
A new compressor is sealed and pressurized with Nitrogen gas. When fitting a new compressor, slowly release the sealing cap; gas pressure should be heard to vent as the seal is broken.
CAUTION:
A new compressor should always be sealed and could be pressurized with nitrogen gas. To avoid possible oil loss, release the sealing cap(s) slowly. Do not remove the cap(s) until immediately prior to connecting the air conditioning pipes to the compressor.