A/C evaporator has leak, per dealer after putting in dye. Says $1400 to replace

What is your question?

both the evap and the drier.They put new freon in,(2 wks ago) now cooling almost as good as originally.I was told that a possible fix to seal the leak is something called Red Devil (?),put in with freon and allowed to circulate well,& may evan take doing it twice to seal it. Ever heard of this and is it worth a try? The person who told me about it says his a/c now running great for 8 months. Thanks so much for a reply.