gentlemen, a/c systems are cosidered "closed systems" and never need a refill or recharge, unless there is a leak. a/c shops don't like to spread the word on this, they would rather you come in for a 'recharge', more money.

you had the classic condensor fan dead or slow leak symptom. when the fan is dead the condensor is only being cooled off during air moving across it while driving. if there is a slow leak, the same symptom occurs because there is not enough coolant to maintain proper pressures at compressor idle speeds, but when the rpm's kick up the compressor is able to build pressures with the amount of freon that remains in the system. over time, all the coolant leaks out, and no cooling occurs. what's worse, if the leak is on the low pressure side, in comes the compressor killing dirt.

tried to make it simple to understand, hope that helps. been working on a/c systems for 9yrs now, so I feel I have a pretty good understanding of what goes on in there.

be sure the dye was injected so that next time the leaks are a little easier to detect. some shops fail to put it back in even though it is put in at the factory.