So my local shop looked at the car and determined there was a very slow leak somewhere. The leak took 20 years to reach these levels.
My AC blows thru all vents at low power, but its not really cold at all. Its kind of like a medium warm.

When I hookup up an a/c pro canister to this port right here it shows in the green.



They told me they could fix it with a a/c recharge for $139.99, so apparently there is another port somewhere on the car to fix this. They wouldn't tell me where it is though, so I have no idea where the other port is.
According to them there is a high side and a low side port. Whatever that port is shows it right in green when the a/c pro is connected looking at the gauge with the car turned off.

As I understand this you turn the car on into accessory mode, but don't start it. You then turn your ac to cold and bump it up to full blast.
You then hook up the a/c pro to that port and if it reads in the green at all you don't add any. If it reads anywhere below the green you add some.

Is this the correct proceedure?

 

You need to have it running and then check.I bet it drops WAY down once the compressor runs.The way you are checking it is only showing the system pressure which should be within a few degrees of air temperature with the compressor running.Once it is running.charge it until the gauge is in the green and you should be set.I have to add a little to mine each year as I am too lazy to track down and fix the leak!

 

Thank you, I will definately try that.

 

Wow.....I'm not being a hardass, but its obvious you have no experience with A/C systems, automotive or otherwise. You must have the compressor turning, and, well, compressing, before you can add any refrigerant. They didnt tell you where the other port is, because you could be seriously injured by trying to add a can of refrigerant thru the high side port. In fact, they are different sizes, made that way so inexperienced people don't have a can explode in their face!! Here's a very brief how-to:

Start the car, turn the A/C system to full cold on both zones (if you have dual zone A/C), and turn the fan on as high as it will go. Remove the plastic cap on the low side, which you have indicated. Screw a valve with recharge hose onto a can of refrigerant (R134a). You'll note the end of the hose has a quick connect/disconnect female fitting. This must be snapped onto the A/C port you have indicated. Once connected, slowly open the valve. The can should get very cold, as well as the A/C line you're charging into. You may need a buddy to rev the engine a bit to make the compressor work harder, to make the low side pressure low enough that the can will discharge into it. Honestly, if I were you, I'd probably have the A/C shop do this job, because without a vacuum pump, gauges, and some sort of scale to measure how much refrigerant you're adding, you can overcharge the system, and then it still will blow warm. The C5 A/C system is VERY fussy as far as the refrigerant level is concerned. Best of luck to you, and maybe you could ask the tech to watch what he does, and how he does it, and try to learn. It's not rocket science, but experience is your friend, especially in this situation......

 

Mike,
To properly do this you need a set of gauges and know what they mean. The AC Pro cans do not show the high and low side pressures - only the lows. Over time, there could be gunk built up in the orifice valve (a built in restriction) and if that is the case, a set of gauges will show an abnormal difference between the high and low side. With the cans you never see that.

If you are intent on doing this yourself with the AC Pro can, basically all you can do is add freon while the car it running and look at the low pressure gauge on the can. What will most likely happen is that the system will take some freon and the temps will be cool again. However, you won't know exactly how much freon is acutally in the system.

 

I agree, Ed. I failed to mention the gauges, which I have. I was going to mention the orifice screen, but decided against it because in order to check that, he'd need the gauges and vacuum pump to re-do everything. OP-IF you decide to do this, like we both said, proceed slowly, and add just enough to (hopefully!) to make it blow cold again. Dont know if anyone has priced R134a lately, but I was looking at it yesterday at a place (Meijer) that usually has very competitive pricing. I was floored!! A 12oz can that was $5-$6 a year or two back, is now like $12-$14/can!! The A/C PRO was $40!!!!!

 

Before you go fooling with the charge you will need to determine that your vacuum hose into the cabin does not have a hole in it and that all of the ac system inside the car is working properly . Your system could blow cold on 1 side and warm on the other side ,

 

You are right about prices. R134a is phasing out so I thought I’d stock up on some cans this Spring. I have 2 cars with very slow leaks that I have not been able to find yet so I add some charge each Spring. They may be “phantom leaks” because it I seem to lose charge over the winter. After checking a few places that were in the $12 a can range, I went to Big Lots on a hunch. I got lucky. They had a bunch of the old style R134a cans and were $3.

The original post said he was quoted $140 for an evacuate and fill. That sounds like a pretty fair price if it is a reputable shop.