More thanof likely you have R134A freon, if you do have a slow leak, I suggest that you have a professional inject a yellow dye detected by a black light. If you have a visable leak it will show with an inspection, and repair properly.
〉 Answered on Jul 9th, 2012 by Amanda J. Pierce, MBA "AJ", Certified Mechanic, Project Coordinator; Primavera Scheduler at VIGOR Alaska Industrial Shipyard & BizzM3ch Solutions
You'll have to take it in for service to do this. In order to buy freon you need to have a license and the tools to install it.
Call around to local shops and ask for a cost to charge your system. I know near me there have been a lot of coupons in the paper for this service. It's best to let a professional do it.
〉 Answered on Jul 9th, 2012 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines