Before I decided to repair my leaking ac compressor by order a 0-ring and shaft seal gasket set, I was looking at various Professional grade sealants. There is a product call Super Seal Premium manufactured by Cliplight, that you add to the system and it's suppose to seal any and all leaks wherever refrigerant circulates, as long as the leak isn't too big. If the system will hold a charge for a least a couple of weeks, this stuff claims to be able to seal it. It's an epoxy the hardens wherever it comes into contact with air.
The bigger problem may be finding someone that installs it. Shops anymore don't want to sale you the $50 fix, when they make a lot more money replacing the whole thing with new.
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