A/C Leak at compressor?
 

I decided to start getting my ac system working on my 94 b3000. It supposedly worked very well a couple of years ago. I went ahead and put my gauges on it and found it to be totally empty. Reading 0/0 and compressor never turning on. Pulled a vaccume on it and it held 30m @-27psi. Proceeded to charge it with an oil/freon can and it blew nice and cold. Also had dye in it. Well, found dye bubbling out of what looks to be a blowoff valve at the back of the compressor where the line from the dryer to the compressor goes in. Wtf is this thing? Can I replace just the valve? Entire compressor?

Not sure... might have to put it on the bench and see if you can unscrew it and re-seal. Otherwise sounds like parts swap to me.

https://cimg9.ibsrv.net/gimg/www.ran...101759a283.jpg
The circled spot is where the leak is.

So a friend told me that's the pressure relief valve and that id have to buy an entire new compressor to get one. Looks like it's screw on. Anyone know where to get just the valve?