A/C Problem on a 1996 850 GLT

waterheart776 · Post by **waterheart776** » 31 Aug 2010, 20:12

Hey,

I have a friend I'm helping with her car, she just bought it, and the only thing that's wrong with it is the A/C. Well, they didn't know what was wrong with it, so we did the first logical step: buy a can of refrigerant plus oil (18oz total), and went to put it in. Well, when I hook it up to the low side, the gauge reads 70psi. Knowing what I know, that's not right. Now, without having the correct car hose setup to hook into both sides (high and low, and a hose for the can of refrigerant), there's no way to determine what is up. I know that the meter on some of these store-bought recharge kits is a joke, but when I depressed the button, none went in (I heard a tiny hiss, but could tell nothing was happening), and I was afraid that if I kept the button depressed, that something bad might happen to the can, my hand, or who knows what. I have no idea where to start. Nothing else is wrong with the car at all. Two owners, 195,000, runs like a dream, all maintenance done at the same Volvo shop. Only problem is, the cost to try and figure out what's wrong with the A/C is prohibitively expensive (and the A/C is the only thing not working on it). Any advice on where to start looking, or if that gauge was full of malarkey or not, would be of GREAT help, and greatly appreciated. Without an ability to pull a vacuum on it, I don't know if there's much I can do. Was the port next to the radiator on the passenger side, the suction side (low side) port?? (because the hose fitting slid right on)

Sincerely,

John
Frederick, MD

Post by **Ozark Lee** » 31 Aug 2010, 20:38

Elaborate further.

70 psi on the low side (which is all that we can get - there is no high side pressure port) is low if it is a hot day. The plus is that you can likely dump a can of R-134A in and least cool things off and buy time.

The evaporator coil is the weak link on the A/C system and if is a time consuming job to fix, you need to remove the dash to get to it. It is not as intimidating as it looks but it will take a lot of time.

http://www.woodjoiner.com/volvo/

Was the port next to the radiator on the passenger side, the suction side (low side) port?? (because the hose fitting slid right on)

Yes - and that is the only port you have.

...Lee

waterheart776 · Post by **waterheart776** » 31 Aug 2010, 21:07

Lee,

I noted the pressure on the interdynamic gauge on the 18 oz. can of refrigerant. It was just into the red from the yellow on the gauge, around 70psi.

I could sense resistance (that is, the feeling that the refrigerant was making it into the tube leading into the fitting, but not past the fitting itself). If the schrader valve is bad/defective, I'd be surprised. I've never charged a Volvo before, but normally you can feel the refrigerant flowing through the blue tube connecting the bottle to the suction port; this was not the case here). I didn't want to cause damage (and stopped), because I was not 100% sure of what I was doing, so I stopped to take the time to research the issue to make sure that I was accurately assessing the situation, by having an understanding of how these systems are setup versus the stuff you usually find on the market. I do not own a Volvo, but have worked on the old B230F engines before, and A/C is pretty much the same on every car, with a few exceptions (mostly in the foreign cars category).

I had the car on, A/C set to max cool, with the engine revved up to 2000RPM. The compressor was cycling on and off rapidly at the beginning (usually indicative of low refrigerant charge), so I hooked up the bottle and started to charge. I had to pull up on the fitting's release button to get it on all the way (but that's normal in most instances with the cheap plastic fittings). I heard the familiar hiss, and I looked at the gauge: a little before 70PSI, just into the red from the yellow on the color-coding. I tried depressing the trigger anyway, figuring that Volvo is different, and/or the gauge might not be reading correctly. I did not feel the usual release, and just heard refrigerant hitting the tube. I don't know if I should've wiggled the fitting or not, but that's usually a bad idea. Refrigerant burns are not fun. I put my hand on the tube, and didn't feel refrigerant flow. I released, and tried again. A slight hiss, but nothing else. I held it for a while, then thought better of it, and let go. I used a rag to disconnect the fitting, and there wasn't much more than the usual amount released, which leads me to believe that it either didn't get into the system because the compressor wasn't engaged (because I noticed towards the end that even though the A/C was on, the center wheel on the compressor was not turning), or there was something else wrong, even when the compressor was running....or, the schrader valve is defective, but somehow that makes no sense in this instance. So......compressor shim? Evaporator coil? What else could possibly be bad on this car's A/C system (I get the feeling the answer is: LOTS.....which is what leads me to believe THAT as the primary reason for the shop wanting to charge so much, because my friend thinks it's going to cost 1,000 dollars to fix. I don't know if this is accurate, but I do know how expensive the parts for Volvo can be, so......).

--John

waterheart776 · Post by **waterheart776** » 31 Aug 2010, 21:40

I looked at the evaporator replacement procedure through the PDF link. Wow. Doesn't look that hard, but wow. I will pass some of this on to her.

Post by **Ozark Lee** » 31 Aug 2010, 21:42

John,

Since you actually have pressure I am going to pretty much rule out the accumulator as the fault/leak. People will yell at me but I turn the can upside down and dump liquid into the the system until it maintains a steady "compressor on" pressure. Until you have a constant compressor on the gauge readings don't mean much. I did buy a cheap gauge set so that I can kinda watch what is going on as I fill the system. I think I bought the gauge set at Advance but Harbor Freight has a similar set for under $40.00 that will let you fill and monitor pressures simultaneously as you add refrigerant.

Chances are there is a leak in the evaporator but you can keep your friend cool at about a can of R-134A/week. My summer has been trips to Wally World to buy the cheapest 134-A I can find. At some point I will finish my dental work and my geographically challenged jobs and finally have enough time to work on cars.

It is very hard to overcharge the system.

...Lee

waterheart776 · Post by **waterheart776** » 31 Aug 2010, 21:52

And let me just also say that I would like to own one of these cars, but damn! When things go on a Volvo, they GO. Holy moly! That guide.....good grief! My Acura isn't nearly as complicated in some respects, though I do know that taking a dash apart is NOT fun, no matter what kind of car it is.

waterheart776 · Post by **waterheart776** » 31 Aug 2010, 21:59

Thank you Lee! Your advice has been very helpful, and enlightening. I will take it, and try tomorrow. I will update on how everything goes.

--John

Papas850 · Post by **Papas850** » 31 Aug 2010, 22:43

I think 70psi (if your reading right is WAY OVERCHARGED) !

Retired MVS Contributor · Post by **Retired MVS Contributor** » 01 Sep 2010, 07:50

Was the compressor running when you were trying to add refrigerant?...If it was, then papas850 is right, it is overcharged...If the compressor was NOT running, then we need to know what the ambient temperature was at the time you were adding refrigerant...If the temperture was in the 90's the static pressure should be 104 PSI and 70 PSI indicates it is undercharged... BTW, the system is not leaking badly or the pressure would be zero...

All recharge kits are not created equal, thus the difference in price...I suspect that the schrader valve is not being depressed by the adapter fitting...I would try a different one...Some adaptors have a built-in adjustable shrader depresser that you screw down after connection is made, and back off when you are finished...That way you do not lose any refrigerant when you connect and disconnect...It is important to keep moisture (from humidity) from entering the system...After the can is connected, but BEFORE you puncture the can, loosen the hose connection at the gauge for a second or two to let the system refrigerant push the air out of the hose...The longer the hose, the more important this is...

Finally, IF the system is undercharged, and IF the shrader valve was being opened, and IF the compressor was running, then it is possible that the compressor is toast because if it was good it should have pulled the low side (suction) pressure down...But there are other possible reasons such as a blocked accumulator or orifice tube...

waterheart776 · Post by **waterheart776** » 01 Sep 2010, 09:27

The compressor WAS running at the beginning, when I turned on the A/C. It was cycling on and off on about a 5-7 second interval (I believe). I noticed towards the end when I was trying to charge it, that the reason it wasn't charging was because the compressor wasn't engaged (in other words, the center wheel was NOT turning). The compressor went to "OFF" and stopped cycling about 1-1and1/2 minutes into the process. Maybe I should've been quick and gotten it in when the compressor was engaged??? I do not know what caused the compressor to cut off. My brain wants to say "Thermal Expansion Valve", but cars do not use the same cheap spring-type TXV that most of your home units use. They just use a small orifice to force the refrigerant through.

I believe that the ambient air temperature was 82 degrees at that point in the evening.

I suspect the same thing about the schrader fitting, which is why I mentioned it. I need to get a set of gauges, because you can adjust the fittings on those. The all-in-one cans? FORGET IT.

Bad accumulator? That makes sense, though I'm not sure where it is on this car, as I do not have the fortune of having a 9,000 or so page factory service manual for her vehicle, as I do for mine.

I will try a different fitting and see if that is not the problem. As tempting as it is to just turn the can upside down and dump liquid, I know I wouldn't do that to my car, and I don't want to do it to my friend's. Most especially when I'm not sure that her problem is the same as the other guy on here.

I'm betting that the schrader valve might have been the problem, but what (other than low charge) would cause the compressor to cut off (other than the compressor being Tango Uniform)?

--John