You can have a mechanic inject a black dye into the high side of your a/c system line. Any leaks that are detected will show the source of leaking freon. Your air compressor may have become faulty as well. If that is the case, the "orifice tube" in the system (screen) should be changed as metal shavings from a faulty compressor in the a/c system can cause damage to the new devices after installation an circulation.
〉 Answered on Jun 13th, 2009 by Amanda J. Pierce, MBA "AJ", Certified Mechanic, Project Coordinator; Primavera Scheduler at VIGOR Alaska Industrial Shipyard & BizzM3ch Solutions
Take your car to an authorized dealership or ASE certified repair facility for a complete diagnosis.