Adding refrigerant - does it ever fix the problem?

So the hotter it gets this year, the more of a crisis I am facing with my weak, not-very-cold ac on my 2001 2.2 5-speed manual Cavalier. I had the original compressor and associated parts replaced after 7.5 years back in September of 2008 and that was the only time anything has ever been done/changed/added, etc…to the whole system. Since it started to get hot - a month or 6 weeks ago - I have been running the AC once a day and it takes a LONG time…usually at least 15 minutes of inside/recirculated air to get cold and this is only at night after dark. I took my first highway drive 2 days ago and in past years when I did that, after having driven about 30 minutes or more on the interstate with the AC running - the evaporator and/or drier would ice up and I’d have to turn it off for a few minutes otherwise the air flow would drop to nothing. Well this time, I took this drive in the afternoon sun with it about 90 degrees outside and even after 1 hour of running constantly, it really barely ever even got cool. I opened up the hood at the end of this trip and the drier was just cool, not cold and nowhere near having any ice.

Now back over this past winter I noticed a compressor oil leak spot on the driveway. That was the signal of the end of my first compressor so I was afraid that the compressor would be dead when I tried it this year.
The leak is from the bottom of the compressor - from the plug there, which apparently is the “control valve”. Does anyone have any experience with the o-rings on that thing leaking and/or replacing the control valve to fix the problem? Based on my research, that would be the thing to try but I am having a hard time finding anything about the procedure or anyone who’s done it. I’ve been using the system for 6 weeks and the compressor is working fine, so is the clutch and no troubling sounds or any signs of a problem - other than the cool (not cold) air. I have been afraid to add r134a because my thinking was that it might blow the apparently small leak (where the oil dripped out the bottom of the compressor) wide open from the higher pressure and then I’d be in a lot worse situation that I cannot afford to have fixed. So I have just been dealing with the situation of having to run the system for a long time to get it cold. But that isn’t going to work much longer as temps near 100 over the next month.

Here is my question. Since there has been no refrigerant added to the system since September of 2008 (8.5 years ago) - is it to be expected / normal that I just need to add some now to fix the problem … OR…are my fears of what I described legit - that adding any pressure to a system that has this leak will just blow it open and I’ll lose what I have now?

Thanks for your thoughts/advice. Oh, and I can’t afford to take it to a shop so save that suggestion for someone who isn’t as poor as I am (which is just about everyone).

If you are leaking oil, then you are almost certainly leaking refrigerant. I am not familiar with the problem you describe with the compressor, but I would bet that adding a can of 134a would significantly improve cooling for a while. Lots of cars require a can be added every two to four years. Very few closed systems are absolutely leak free. Since your compressor is leaking oil, though, adding refrigerant now will probably be a very short term band-aid.

Adding refrigerant won’t make the leak appreciably worse. The refrigerant kit comes with a a pressure gauge that, while it is no substitute for a professional gauge setup, helps keep you from overfilling the system. On my old BMWs, I have to charge past the green zone on the gauge and into the yellow on a moderate temperature day before the air blows cold. As soon as the air blows cold, I stop adding refrigerant. Mine is a dangerous game though, because adding refrigerant based on air temperature at the vents is rather like adding air to your tires based on the way they look. You can easily go too far. Having too much refrigerant makes it less cold and can damage the compressor.

What’s leaking is actually a combination of oil and refrigerant. There is no separate compartment for oil and another for refrigerants. Sooner or later you will have to get the leak fixed or the system will run dry and the compressor ends up dead.

You have two choices, 1 properly fixed the leak or 2, simply add a can of refrigerant and hope that it will last.

Fixing the leak should be easy if indeed all that needs to be done is replace the O-ring. Just for kicks, you can re-tighten the bolts in the even they got loose, but I doubt that.To properly do it the system must be evacuated of all refrigerants first to prevent the stuff from escaping into the atmosphere when the coupling to the compressor is removed. Once evacuate you can remove the coupling and replace the O-ring, before refilling the system with refrigerants.

You can also take a chance and simply add more refrigerant. Just follow the instructions on the can and do not overfill it. You might be lucky for this summer if the leak is not too bad, but keep in mind that sooner or later you will have the same problem again. You are just pushing off the inevitable.

I have upon occasion added refrigerant with leak fix
and it actually worked!

I’ve heard very bad things about the refrigerant Stop-Leak, but have never used it myself.

Simple answer: yes- adding refrigerant may temporarily fix your issue. Personally, I would give it a try.

Long term answer- you have a suspected leak. That is not likely to get better on it’s own. Clean it off as best as you can, and keep an eye on how quickly it returns. Adding refrigerant is only adding refrigerant, not adding oil- and the system needs that oil to not only lubricate the compressor, but also to help move the refrigerant thru the system.

Just get the stuff that also contains oil. As a matter of fact, most over the counter re-fills contain oil.