Usually I would search this but I'm on my phone and it's a pain to search.

Anyway, I recently filled my ac with a can of whatever it is, cold stuff, but it will only blow moderately cold for about 20 minutes then blows warm. Is it possible I need another can of cold stuff? But if I park for a while then turn it back on, it's cold for another 20 minutes. What gives? Is another can my solution? Or condenser is going out?

 

Easiest way, take it to a shop, pay the 89 bucks for them to charge it and leak test it, then be on your way. They will suck all the old out, vaccume the system so it is free of moisture, then charge to the correct amount, plus look for leaks.