outside coil probably dirty causing high pressure switch to trip or compressor thermal protection to throw go to a supply house get some sodium hydroxide condenser coil cleaner mix it about 1:4 and soak the outside coil down real good with a pump up sprayer the whole coil should be covered with foam inside and out once you get it on thick enough and rinse it off after 4 or 5 minutes make sure you rinse good its corrosive stuff. you said the fan shuts off and blows hot air so im assuming you mean the compressor quits running because a fan cant blow anything if its shut off.