I'm replacing my first piston type compressor on a 1979 - 240D mercedes and would greatly appreciate any sound advice. I've replaced many modern compressors but never one this old. Does the system require addition of oil to the gas stream like a modern system? If so what type and how much? Do you need to add oil to the crankcase of the York piston compressor? If so what type and how much? When I disassembled the existing system there was no oil in the gas stream but there was oil in the old compressor crankcase. Thanks for any help.