Hi All. I'm looking to sell my truck soon and I was charging my girlfriends ac and I figured I would check mine just to see if I could get it a little colder. I put the gauge on and it read a little low so I charged it just a bit. It worked fine for the rest of the day, maybe even blew a little colder. The day after that I start the truck up and it only blows hot. I look under the hood and it seems like the compressor tries to kick on and quits. The next day my uncle says I may have over charged it so I went to try and let a little out and the compressor isn't even trying any more. I can't let off pressure it it wont compress. I understand that there are an array of problems it could be but where can I even start. I don't have money for a mechanic and id hate to drop the price so significantly on the truck trying to sell it without a working AC. Texas summer is in full swing so I'd be lucky to even find a buyer.
Thanks in advance,
Nate

 

At this point you need a set of gauges to see where you stand. The right way is to pull the refrigerant out, pull a vacuum, then recharge with the proper amount of refrigerant.

Short of that, if you're absolutely positive you overcharged it, you can engage the AC (max cool), then slowly bleed pressure until the compressor comes on. It should stay on longer the closer it gets to a normal amount of refrigerant.

Once you have the compressor coming on and staying on for longer than 10 seconds, measure the vent temp. 55-60 degrees is where to stop.

But I can't overemphasize you really ought to try and find an AC guy. Craigslist might be good for an independent mechanic who wants some quick easy cash....

 

The observation that your compressor will not remain on indicates that you have no pressure at all, meaning you lost a significant amount of Freon, and the pressure valve is doing what its supposed to do; turn off the compressor.


One possibility is that the valve you attached the "miracle" A/C pro can of Freon to is the culprit unless by freak of bad luck, a leak developed elsewhere (did you perhaps lean on a hose while working on it?). Or by adding the Freon, it created pressure and blew an old weak O-ring seal on one of the lines.


In any event, the longer you wait to take it to a A/C shop or A/C mechanic for a diagnosis and repair, the more it will cost you. I would strongly suggest you stop charging it yourself, and keep the compressor off. Continuing to do so otherwise will cause the compressor to pull outside air into the system where the leak is, and corrupt the dryer and other areas of the A/C system with moisture.


In most cases, an A/C shop will replace the dryer whenever a leak is found, along with any other repairs needed to correct the leak.