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centizen

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Discussion starter · #1 ·
Hey all,

Been having a recurring issue with my air conditioning on my 2011. I had the system serviced last year to try to fix the issue (third party mechanic, closest Volvo to me is 2 hrs away) but it has still kept cropping up. By law here in Canada, anytime the system is serviced it has to be checked for leaks, and my mechanic said it was properly holding pressure. I have been living with it through the winter but now that summer is starting over here, I'm going to try to get it fixed again.

The system blows ice cold when the car is in motion, highway driving it always works fine. It will keep it's chill for a little bit if I have to stop at a light, and I can rev the engine up it keep it cold if I am desperate. But the longer I stay still or at low RPM's, the warmer the blower air gets. It eventually gets to the point where it feels like it's hotter than the outside air.

I've noticed that if I turn the A/C system off, wait a few minutes and then turn it back on, it seems to blow cold for a bit even if I was idling.

Does this pattern of behavior strike anyone as being an indicator of any specific problem? Sorry if this is a common issue, I took a look through the forums and didn't see anything.
 
Check the pressure at low port when AC is running, it should be around 40 PSI. If not, you can top it up with RedTek, just propane. Dry, plus Proseal can slow the slow leak significanty.(1 year to few years)
 
Discussion starter · #5 ·
What engine? The 6cyl fomoco gas engines have a variable displacement compressor - and the valve that controls that can get clogged or or bad. That will make the ac erratic.
I have the T6 engine, so it sounds like this could be my issue. Are there any resources I could provide my mechanic on getting this sorted out?

AC compressor clutch air gap is too large due to wear, when it gets warm enough, the electromagnet does not have enough voltage to engage the clutch. When it cools down, either due to engine being off or airflow while driving, it works. The fix is to remove shims from the clutch to decrease the gap.
This also sounds plausible. How big of a job is it to get the shims out?
 
Clutch gap is a problem (due to wear) and happens on very hot days after the system has been on for while and the compressor/clutch is very hot. At that point the gap becomes too large due to thermal expansion and the magnetic field can't pull the clutch closed to spin the compressor. I don't think those are your symptoms - that has not been a problem with the 3.0/3.2 compressor. It is a problem on many other 5cyl compressors. If clutch gap is a problem it is easily measured to verify that might be the problem. If when measured and the gap is not too large - that's NOT the problem.

If "your mechanic" is not familiar with variable displacement compressors - perhaps you should find another "mechanic" who is.

Or - some will say your compressor is bad. And a new compressor will fix it - because the new compressor has a new variable displacement valve in it.

Do not allow anyone to put anything into your ac system other than r 134 freon and a little bit of Pag oil.
 
I wonder what the ambient temp was when your system was recharged. If less than 70 F then there is a problem getting enough refrigerant in because variable displacement does not open enough (lack of cooling demand). That is, you can turn the HVAC controls to full cold but if it is cool enough out the system won't chill much and filling it in that state does not really work (what you have to do "shadetree style" is put a can of refrigerant (that has a gauge) on the lo pressure valve and after you open the valve then set the can somewhere that it will warm up while sitting upright. As the can warms it bleeds me refrigerant gas into the low side.

Volvo tells you not to add refrigerant on the low side due to the risk of insertion of liquid refrigerant on the low side and the damage it can cause. So don't tip the can. And find a way to check the high side pressures so you're not overfilled. An inepensive manifold would do.
 
Discussion starter · #9 ·
DO NOT DO THIS......

The other two comments are solid suggestions....
Yeah that didn't seem like a great suggestion to me. I don't think there is any reason to suspect the pressure anyhow.

Clutch gap is a problem (due to wear) and happens on very hot days after the system has been on for while and the compressor/clutch is very hot. At that point the gap becomes too large due to thermal expansion and the magnetic field can't pull the clutch closed to spin the compressor. I don't think those are your symptoms - that has not been a problem with the 3.0/3.2 compressor. It is a problem on many other 5cyl compressors. If clutch gap is a problem it is easily measured to verify that might be the problem. If when measured and the gap is not too large - that's NOT the problem.

If "your mechanic" is not familiar with variable displacement compressors - perhaps you should find another "mechanic" who is.

Or - some will say your compressor is bad. And a new compressor will fix it - because the new compressor has a new variable displacement valve in it.

Do not allow anyone to put anything into your ac system other than r 134 freon and a little bit of Pag oil.
Thanks for the info. I'll make sure my mechanic knows what they are doing, but they are generally quite competent so I would hope that's the case. Worst case I can take it to Volvo, it will just be a bit of a trip.

I wonder what the ambient temp was when your system was recharged. If less than 70 F then there is a problem getting enough refrigerant in because variable displacement does not open enough (lack of cooling demand). That is, you can turn the HVAC controls to full cold but if it is cool enough out the system won't chill much and filling it in that state does not really work (what you have to do "shadetree style" is put a can of refrigerant (that has a gauge) on the lo pressure valve and after you open the valve then set the can somewhere that it will warm up while sitting upright. As the can warms it bleeds me refrigerant gas into the low side.

Volvo tells you not to add refrigerant on the low side due to the risk of insertion of liquid refrigerant on the low side and the damage it can cause. So don't tip the can. And find a way to check the high side pressures so you're not overfilled. An inepensive manifold would do.
I couldn't tell you exactly what the temperature was, but it was filled in the summer when the outside temp was around 86C and I can't imagine they would be air conditioning the shop too much.
 
The variable control valve inside the A/C compressor should be replaced, not very expensive. A rather frequent issue for 5cyl and 6cyl engines in Platform 3 cars:
 
SOunds more like radiator fan control. When the car is stopped it counts on the fan running at a good bit of speed to draw air over the condenser. When you are driving the air gets drawn across the condenser and cooling occurs. So, with AC on and the car stopped, does the fan come on? It is controlled often by a couple of different relays.
 
SOunds more like radiator fan control. When the car is stopped it counts on the fan running at a good bit of speed to draw air over the condenser. When you are driving the air gets drawn across the condenser and cooling occurs. So, with AC on and the car stopped, does the fan come on? It is controlled often by a couple of different relays.
This was my problem a few weeks ago. The harness was loose on the radiator fan. Squeezed it together and the fan came on with the a/c like it’s supposed to. After I did that, A/C was blowing cold at idle again.
 
Discussion starter · #14 ·
This was my problem a few weeks ago. The harness was loose on the radiator fan. Squeezed it together and the fan came on with the a/c like it’s supposed to. After I did that, A/C was blowing cold at idle again.
Wherabouts is that wiring harness? I'll take a peek and see if it's loose.

Good tip on the variable control valve
Image


Is this the variable displacement valve here?
 
SOunds more like radiator fan control. When the car is stopped it counts on the fan running at a good bit of speed to draw air over the condenser. When you are driving the air gets drawn across the condenser and cooling occurs. So, with AC on and the car stopped, does the fan come on? It is controlled often by a couple of different relays.
This was my first thought, sounds like the fan isn't pulling air across the condenser when stopped.
 
Just an FYI. I have been having issues with my AC for years.(2011 S60 T6) I had replaced the compressor, control solenoid, and even the pressure switch/transducer. It got cool but not cold. Just yesterday I replaced the TXV. Now my AC is ice cold. Its hard to get to, you can see it next to the low pressure port under the cowel. I had to take out the false firewall to get enough room to replace it. But it was worth it.

If anyone is going down the same rabbit hole its probably the TXV. Just a tip of you do plan on replacing it. The two screws that hold the TXV to the evaporator are #3 allen screws. It didn't say it anywhere in VIDA or anywhere else, and it took me some time to figure that out. I got the Nissen TXV off of rock auto and transfered the stem that holds the bolt for the lines from the old to the new one.
 
Yeah that didn't seem like a great suggestion to me. I don't think there is any reason to suspect the pressure anyhow.



Thanks for the info. I'll make sure my mechanic knows what they are doing, but they are generally quite competent so I would hope that's the case. Worst case I can take it to Volvo, it will just be a bit of a trip.



I couldn't tell you exactly what the temperature was, but it was filled in the summer when the outside temp was around 86C and I can't imagine they would be air conditioning the shop too much.
Makes sense.

In the back of my mind I think there's likely a simple answer/procedure for setting this thing right that we just don't happen to know about.
 
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