When AC goes out...

[TWMn]

Lee, please verify (I have a '94 855 Turbo) steps and add any missing:
To test and recharge system with a non-cycling (running) compressor.
1. Buy kit with recharge hose and gauge for low pres. connector
2. Jumper low-pres. cutoff switch at firewall (or will it start by itself when adding freon?)
3. Start engine, turn AC on max., recirc.
4. Test pressure with gauge. If presure present add 134A. If no pressure find and fix leak at evap. or accumulator or hoses.

How long can I run compressor while jumped? Don't want to damage it.

[dcaudio]

My AC was not blowing cold air, but I followed some of the hints here and got it blowing cold. The relay (clicking noise) was going off and on about every two seconds. I followed some of the suggestions here and bought a 18 oz (or was it 22oz???) can of 134a that had a gauge attached to the top of it-- it cost $34 at AutoZone. I attached it to the valve behind the passenger side headlight and the meter jumped from about 20 to 40 with every click of the relay. I opened the valve on the top of the can. This was somewhat tricky-- I think I turned it clockwise to puncture the whole in the top of the can and then counterclockwise to open the valve on the can. This got the 134a flowing into the car. The can got a touch cold and withing about 1 minute the relay stopped clicking. I thought great! I popped the hose off of the valve on the car and, to my surprise, gas was escaping from the can. I turned the valve on the top of the can about 10 revolutions and finally the outflow stopped. This was of course a dumb thing to do, but I thought that the thing on the end of the hose would have kept the gas in the can when disengaged from the valve on the car. The smart thing to do would have been to close the valve on the top of the can, but the reason I did not was because I was not sure which way was open and which way was closed. I was not sure because when I bought the can the valve was about in the middle of the range. I understand, in hindsight, that it was not. Live and learn (and hopefully don't kill mother earth in the process!).

With the gas leak from the can stopped, I went to see if cold air was blowing. It was not cold. I frowned. Then I asked the AutoZone guy what he thought and he pointed me toward the gauge. The gauge has a thing that rotates on top of it to specify what range PSI you should aim for DEPENDING on the air temperature on earth, which must have been 120 F in this black top parking lot on the south side of Atlanta, GA. So I was sweating. And I needed a shower. But I guess those are details for a later story. Basically the hotter it got the higher I needed to see the meter read out. I was currently around a solid 25 PSI (without the relay clicking on and off it was now steady) and warm air was still flowing out of my vents. So I re-attached the hose/can of 134a and opened the valve. I let it pump in until the meter read about 50, which was right at the edge of the red zone. Then I held my breath. I held my breath because I thought the car would either now explode or there would be cold air blowing out of the vents. I held my breath because either heaven (a working AC) or hell (an exploded car) was in my near future. I should not have held my breath in the Atlanta heat. With my apprehension/delight gauge going from one end of the spectrum to the other, combined with the heat, I nearly passed out in the AutoZone parking lot. Luckily I started breathing again and everything was alright. Really, it was more than alright. I put my hand in front of the vent and, lo and behold, there was cold air. I said, "Yee Haw," as they are prone to do in the South. I wonder how long it will last before it leaks out again. But right now I am in heaven. Well, I don't really believe in heaven, but with cool air blowing I gotsa smile on me face.

[BlackThunder]

I know this is an old post but my AC just went out last Thursday and in MN we've been in a near drought situation with temps in the 90-100s for almost 2 weeks now.

Anyway, the unit was low on refrigerant so I recharged it like I had done in the past. No problem.

I must have over charged the system since it would kind of "freeze up" the fan when on for a long time. I'd just turn off the AC, and the recycled air, and wait for the system to warm up a little and it would work fine.

Then last Thursday the clutch stopped engaging. Is this something that I can use the "bread clip fix" on or am I going to be in need of a new compressor all together?

I'll be going in for an oil change soon and I'll ask about having the unit repaired but I fear the cost will prohibit me having the mechanic install a new compressor on my 97 850 NA. - if that is the problem.

So "bread clip" fix first? Am I candidate for this to be successful?

Dustin

Bread Clip Fix Link (I had a hard time finding this link):
volvospeed.com/vs_forum/topic/80181-850-ac-clutch-gap-fix/

[jimmy57]

It shouldn't freeze up unless it is overcharged or if the pressure cycling switch is faulty. The bread clip fix would be for a system that cools OK for a few minutes, meaning compressor comes on, but quits cooling later because the compressor is not running later. Later being 10 minutes if weather is cooler and maybe a lot longer if it takes a while before car is cool enough inside that you then turn down the fan speed.
The pressure cycling switch can also prevent compressor from coming on and it is easy to check. There is a black metal line on passenger side of engine compartment behind engine. It comes out of firewall next to a silver/aluminum line that is smaller. On the black line is a silver and white switch with a black connector on it. If you depress the metal loop on the side of connector and unplug it. Now with engine running and everything set so the A/C should be running, bend a paper clip into a "U" and bridge the two metal terminals down in the connector. If compressor clicks in and starts running then go to a part store or dealer and get the thermostatic switch. I looked at Autozone website and they call it a/c clutch cycle switch. $21.99

[byeboy]

Are you sure you are actually turning it off? On the electronic climate control unit the A/C light illuminates in the Off position rather than the On position.

...Lee

'just another little trick from Sweden! Even the manual says when the light is on, so is the AC...which leaves one to wonder about the recirc switch right next to it...because when its on, it IS recirculating the air.

[BlackThunder]

It shouldn't freeze up unless it is overcharged or if the pressure cycling switch is faulty. The bread clip fix would be for a system that cools OK for a few minutes, meaning compressor comes on, but quits cooling later because the compressor is not running later. Later being 10 minutes if weather is cooler and maybe a lot longer if it takes a while before car is cool enough inside that you then turn down the fan speed.

Yes, I definitely overcharged the system but the clutch isn't even engaging. I'll have to check into the "Thermostatic switch."

Dustin

[BlackThunder]

I guess my main question wasn't answered. Do I attempt the bread clip fix on the compressor before I take it to the shop to have it looked at?

Dustin

[JimBee]

I'm just starting to learn about the A/C system, but I have tried the bread clip fix and it worked until the pieces flew out. I actually used pieces of nylon strap which I had on hand. My next attempt won't be with plastic pieces, I'll be using the wire fix instead. Ace Hardware has a 24 gauge wire I think will work. I tried 19 and 22, they were too thick.

If you're in Minneapolis you can take it in to Tires Plus on Lake Street in Uptown, making sure their A/C specialist is on duty. They have the diagnostics to check out all components of your system, for $34.95. I wouldn't take it to the other shops in that vicinity. I haven't used TP for A/C, but they were recommended by a reputable parts supplier and if something is very mysterious and I can't solve it from this site and I really want an answer I'll be giving them a try.

Jim Bee

[TylerCote]

Just added .015" shims to the compressor clutch on my 2006 S40. It took about 1/2 hour total including taking off the wheel and fender underskirt. One way to make sure you don't have an electrical issue is to check the clutch solenoid is energized by checking for the presence of a magnetic field with a steel screwdriver. If the coil is energized the pins on the pulley will attract steel somewhat. Compare this to when the AC is turned off to be sure. AC works like a charm! Thanks to whoever described this fix first!
You saved me $800. I'll add a picture if I can do so on this thread. ~ Tyler.

[cjbmustang]

Yeager...check your temp. sensors located above the grab handles above your doors. Maybe some lent in them...blow them out gently or vacuum out and see if this makes a difference.

On a related note...have heard of AC's freezing up, not allowing cold air to pass through, thus blowing warm air until the unit thaws out and then you have cold again. Not exactly sure why this would happen, but others will chime in...too much gas pressure? Bad clutch gap? Not sure.

this happens when the evaporator freezes. the clutch should cycle on/off. the length they cycle is usually controlled by the low pressure switch. under the switch there should be tiny adjustment screw which should only be turned one blade length at a time and then check the temp. or water/moisture is somehow getting in there and icing up the fins...