A/c continues to go hot
 

my 08 f250 king ranch has been at the dealership 4 times in the last two months because the ac continues to go out. Complete dash removal twice. Found a leak on the shredder valve... Changed it. Also replaced the evaporator . They charged it the last time, it was parked for a week and I started it up and no ac. Took it back to ford and they said there was no freon. They removed the dash again, put dye in and can't find a leak. They claimed they used a black light and Cannot find leaking dye anywhere. I picked it up today and the ac works but prob not for long. Any clues?

Id start by not taking it to Ford. Those idiots arent interested in fixing your ride. Id find an independent shop. Ive been chasing an AC problem with my truck for almost two years now after a full system replacement from a damn dealership. Stupid me.

Check your paperwork and see if you get the same mechanic, if so ask for a new one. Alot of times they will give the vehicle back to the mechanis who fixed the first time for whatever may be their reasoning, he is mentally stuck now. Need new mind on it

Buy the light similar to what they use to detect the leak yourself! Schrader valves have been an issue for leaks. With the dye in there, it should be easy to find.