It would not be wise troubleshooting to replace the compressor just to see if it is the problem. It is indeed a distinct possibility, but there's no need to shoot in the dark.

Do you have access to nitrogen? If so, put in a couple ounces of refrigerant and then pressurize the system to a couple hundred pounds with nitrogen. If you have CO2/Argon for a MIG welder, you could pressurize with that. With a leak as big as you describe, have the sniffer ready to go as soon as the system is pressurized. Verify the leak before replacing parts.

Hope this helps.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

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