Who do I hear a rattling noise whenever I turn on my AC

Many vehicle ac systems wear out from one major problem from a factory sealed system always under pressure when used or not; the eventual leak releasing refrigerant. A slow leak resulting in loss of refrigerant often creates rattling due to the loss of refrigerant and less oil lubrication in the compressor, the source of rattling. Ac repairs are not diy friendly despite all the refill kits available from online and auto parts stores. If a leak occurs, refill kits with sealer can do more damage with a temporary fix that may not be long lasting. If a repair shop is used and they detect sealer in a system, it can contaminate their equipment where they may refuse to work on it. The worse case scenario for car owners attempting incorrect repairs; repair shops rebuilding the entire ac system because of sealer use; a very expensive lesson on how not to perform diy repairs. Your choice to learn what's required to make repairs or pay professionals with expertise.