Air Conditioning Trouble

[Revsputin]

Trouble with the air conditioner (A/C) started about 9 months ago. Everything will run normally for a little while (time varies depending on temp outside) - blows with a force commensurate to the driver/passenger selected temp, and blows nice and cold - but then the coldness stops and the air continues to blow warm, humid air. When this happens, I can hear the compressor shut down and the A/C light goes off on the dashboard (A/C Off light comes on); and if I had recirc selected, it will stop recirc and commence... non-recirc (is that what that's called?).
Like I said, the amount of time that the A/C runs depends on the temp outside; the hotter it is, the less time the A/C will run. It also seems that if the car isn't moving, the A/C will run for less time (it does better on the highway, and poorly in stop-n-go traffic). If I stop the climate control all together for a little while (put the Auto/Manual setting to the '0' position), I can restart the A/C again for a little while - and then it's the same thing all over again.
I've taken it to a couple mechanics, and they have simply recharged the refrigerant. But that didn't solve the problem.
This may also be relevant: The A/C and Recirc lights flash for about 5 seconds when you turn on the car; but that's been happening for years, so if it's relevant, it was only warning of a problem way down the road.

I'd really appreciate any advice or tips as to what the problem might be. The car is about 11 years old now and we've never had any work done to the A/C system, so I suppose it may be time for something to fail. I'm a budding DIY-er, and I'm hoping to be able to do the necessary repairs myself - I may need a little extra guidance on that, though...

- Vehicle info: 2000 S70, SE with 200,130 miles (went over 200,000 just this week - very proud!). It's U.S. spec (bought it in the U.S. back in 2003) but I'm living in Naples, Italy right now... and it's getting to be pretty frickin' hot!

Thanks in advance!!

[537playing]

I find this site interesting reading. Perhaps you may find something to solve your problem. The link takes a while to fully download.
http://www.ariazone.com.mk/pdf/Automoti ... Manual.pdf

[vjaneczko]

The blinking lights is an indicator that something is amiss with the HVAC system. Some have said the number of blinks is a code, some say it's nothing.

A few things to search for; AC clutch adjustment & evap replasement.

[Flybri15]

I'm no AC expert but what your discribing sounds like the system is working fine but gets too cold and freezes up. That can be caused by a clog in the lines. There is a valve that usually the suspect in cases like this. Once the lines freeze up you wont get any circulation and the high pressure will cause the compressor to kick off to save it, you might even hear it cycling on and off when its doing this. The outside temp will vary how long it will work, the hotter it is the more demand on the system the sooner it will fail. I know you will have to have all the freon evacuated and the valve replaced but the bigger issue is what caused it to clog? On my Mustang it was the drier that failed and clogged the entire system, and caused the compressor to fail, so I basicly got to replace almost the entire system, and that runs into some big bucks. Also I would wonder about what the AC mechanics did, they should have been able to determine the freon level based on the pressures as the system worked, ya might wanna take it somewhere else. Good luck I hope this helped.

[Revsputin]

I appreciate the replies and info I've gotten so far.

Due to the combination of a lack of time to really devote to the issue and plain ole wishful thinking led me to attempt to just re-charge the refrigerant with one of those DIY cans of R-12. I did mention that this has been done before by other mechanics - twice - but this would be such an easier and cheaper fix...

I didn't have much luck the first time I tried this a couple weeks ago. As most of you probably know, the DIY cans of R-12 charge from the low-pressure side of the refrigerant system - and that means you can only charge while the compressor is running. When I first tried, the compressor would only run for about 5-15 seconds and then disengage for about 30 seconds or so. The compressor went through this cycle of run/stop for about 4 or 5 minutes and then it would stop trying all together. That meant that there wasn't much time for me to recharge the system. However, during the times when the compressor would run, I could see on the pressure gauge that came with the can of R-12 that the pressure was far below where it should be....

So, that led me to trying one more time today. The first time the compressor started up, I was ready for it, and although it did cutout a few times, after a couple minutes of charging, the compressor stayed engaged! I emptied out the can of R-12, raising the low-side pressure to 39 psi which is in the band of 'good pressure' according to the can. (I'm not sure what Volvo says the pressure should be.) And the A/C was blowing nice and cold for the 5-10 minutes that I felt like sitting there and enjoying!

I plan to continue checking the pressure every couple days to confirm this, but I suspect that I just have a slow leak in the refrigerant system. When I grabbed that can of DIY R-12, I saw some other cans of stuff that claimed to 'seal the refrigerant system'. Has anyone had any success with these products? If that's not going to work for me, I'll have to try to locate the leak - can anyone suggest how I go about doing that?

Thanks!

[daddyk]

Hope you just misprinted that R-12. These run on 134a

[Ozark Lee]

R-12 is absolutely a bad thing to mix with the R-134A.

You problem sounds like a compressor clutch gap problem based on your description.

This thread may help you out:

https://www.matthewsvolvosite.com/forums ... c&start=20

...Lee