I have a 2007 Mustang V6 that leaks freon slowly. I can charge it fully, and within 5 days it's nearly gone.
I've used an electronic leak detector, and no component seems to be showing a leak, except the schrader valves - with the high side seemingly leaking a lot more than the low side. I've put it around the compressor and even in the air vents but the only place it beeps more is around those schrader valves.
So I evacuated the system and attempted to replace the valves. Both were so tightly frozen that I could not unscrew them. I pushed them in and out and vacuumed the area around them from debris.
I pulled a vacuum on the system and it went right on down to the place near negative 30 inches and stayed there for 30 minutes. Then I left it for 20 minutes and the vacuum held. So I closed off and removed the high side hose, leaving that hose off, I turned off the pump again. After 20 minutes there was no vacuum loss at all. I put the hose back on the high side, kept the vacuum and there was no vacuum loss with the low side off of the hoses.
So I put both hoses on, pulled a vacuum for another half hour and recharged the system. 5 days later, I put the gauges back on and the system appears to be slowly getting low on freon again.
Any suggestions? Take it to a shop and let them replace the shraders for good? It looks like the low side schrader is part of the receiver/dryer so I guess replacing that would work for that one. But the high side is part of what looks to be an expensive hose. Should I just replace it anyway and try it all again?