How do I locate a freon leak in my A/C system?

A mechanic replaced the compressor, accumulator, hoses, pretty much everything on my old 88 F-250. It works for about a week, then..... hot air.... again. I keep taking it back to him. He gets it back to me, and a week or so later.... hot air again.





What is the problem? How should he locate the freon leak?





What's he doing wrong? How do you locate the problem?

How do I locate a freon leak in my A/C system?
there is a dye you can put into the system that shows were the leak is under a black light he can also do a pressure test to see if the system is bleeding down
Reply:A leak that empties the system in a week, should be easily to locate and would prevent you from properly apply vacuum to the system in the first place.


After locating the leak using a dye or a leak detector, applying vacuum and making sure the vacuum does not get lost after a couple of hours, it is the verification that all the leaks were found. Do not waste more freon if the vehicle can't pass this test.





Because the age of the truck, you will need also to perform a complete visual on the evaporator and condenser units. you could have a rusted system that will develop additional leaks due corrosion. (a improperly filled system will contain humidity inside that will slowly but surely corrode the lines)
Reply:If it's a big enough leak, with your eyes. Turn it on and look. Where ever you see what appears to be steam coming out, that would be your leak. If it only last a week on refill, it would seem to be fairly large.





For smaller leaks you can get the leak detector, which then can be seen under a special light while wearing the special goggles, but as I said if it runs out in a week it has to be a huge leak.





Keep taking it back until he fixes it, but after that I'd seriously think about a new mechanic.