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Discussion Starter · #1 ·
So try not to dog on me too much guys. After replacing the Expansion valve (which was very gunked up) my intermittent AC problem seemed to subside, but as it has gotten more hot here in TX, it came back even worse than before. Since I was still getting cold AC at highway speeds and engine fans are all working, we decided to replace the condenser and drier.

Well, after charging it up and letting it sit for awhile, the AC was finally blowing cold! But then as soon as I started driving again particularly in city level traffic, it started to heat up. Almost feels like a humid heat. I’m really stumped here because we’ve tried everything besides the physical lines or the AC compressor itself, which kicks on and off (yes visibly confirmed) when the AC is turned on and off. Charge is around 65 PSI in 80 degree weather. I don’t know what the problem is. Sometimes my blower seems to blow differently? Like it’ll just have a different tone of airflow.

Anyway, as I sit here and write this, AC full blast in 77 degree temp, My ac is blowing hot (not ambient temp) but hot air. Sorry for my incoherent rambling but I don’t know what else it could be. I’m tempted to take it to someone but don’t want to fork over 1k or more for something I could just be forgetting that I could fix.
 

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gunk = contaminated system, How much gunk?, So, guess what, it gunked up again... requiring complete flushing of system and components, ..And, you didn't flush the system before adding the new components and most if not all condensers on cars since the late 80's are dual row and unflushable ...So.... you'll be buying another one. Receiver/ driers are usually filters ...sooo .....hard to flush those also as it ruins the desiccant which is the " drying" part of a receiver/ dryer.....you'll be getting another one......or......maybe you'll get lucky and someone will say, aww man, you can flush, recharge it and you'll be good to go.....and it'll work.....or not again
it's 9:18 and i'm heading to bed to catch a plane at 6:30 am..... 3:45 wake up....so, i'm too tired to get detailed, tomorrow maybe.

i told ...you it's a process....but you won't listen.....
 

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Charge is around 65 PSI in 80 degree weather.
As explained previously, a low-side pressure, alone, is not a valid tool for diagnosing an A/C system that is not working properly. The only time you can use low-side pressure in isolation as a very rough estimate of charge level is when you know that the system is working completely correctly. A/C techs either charge by total refrigerant weight (far and away the most common method for automotive systems that are precisely known sizes) or by calculating superheat and/or subcooling (usually these are used in custom systems like home A/C where the distance between the compressor/condenser and the evaporator can vary extensively).

If the air coming from the vents is actually hot, not just ambient (you have measured vent temps with a calibrated thermometer or thermoprobe, right?), then the problem could be in the dash vents or even the computerized climate controls. It's possible that a blend door actuator is faulty and leaving the system in "heat" mode, allowing air to pass over the heater core or (less likely) that the computerized climate controls are wonky and telling the system to heat the car up instead.

I maintain my recommendation from the previous thread: Take this to a professional for a proper diagnostic. Otherwise you're just going to continue throwing parts at this and being frustrated. Look at it this way: If someone had told you at the beginning that you could choose either to spend $1,000 and have the issue fully taken care of (likely with a warranty on replaced parts) within a few days or that you could spend weeks without a properly functioning A/C, spend money on several new parts, spend your time working on the car instead of doing other things you enjoy, and still not have properly functioning A/C, would that $1,000 be worth it? I run this sort of comparison in my own head a lot.
 

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Discussion Starter · #5 ·
Charge is around 65 PSI in 80 degree weather.
As explained previously, a low-side pressure, alone, is not a valid tool for diagnosing an A/C system that is not working properly. The only time you can use low-side pressure in isolation as a very rough estimate of charge level is when you know that the system is working completely correctly. A/C techs either charge by total refrigerant weight (far and away the most common method for automotive systems that are precisely known sizes) or by calculating superheat and/or subcooling (usually these are used in custom systems like home A/C where the distance between the compressor/condenser and the evaporator can vary extensively).

If the air coming from the vents is actually hot, not just ambient (you have measured vent temps with a calibrated thermometer or thermoprobe, right?), then the problem could be in the dash vents or even the computerized climate controls. It's possible that a blend door actuator is faulty and leaving the system in "heat" mode, allowing air to pass over the heater core or (less likely) that the computerized climate controls are wonky and telling the system to heat the car up instead.

I maintain my recommendation from the previous thread: Take this to a professional for a proper diagnostic. Otherwise you're just going to continue throwing parts at this and being frustrated. Look at it this way: If someone had told you at the beginning that you could choose either to spend $1,000 and have the issue fully taken care of (likely with a warranty on replaced parts) within a few days or that you could spend weeks without a properly functioning A/C, spend money on several new parts, spend your time working on the car instead of doing other things you enjoy, and still not have properly functioning A/C, would that $1,000 be worth it? I run this sort of comparison in my own head a lot.
It’s probably worth noting that I did charge by weight (29Oz) and yes I was getting hot air at that moment in the 90s. This is rare in cooler weather like last night, usually it blows whatever temp it is outside if it’s not blowing cold; followed but an extreme feeling of humidity. It’s seems like the change in temp always occurs during a change of moment. For example, could be blowing cold while parked and when I start driving it’ll get hot or vice versa. Be driving and it’s cold, hit a stoplight or slow down substantially and it’s hot. (In this context, hot as in blowing around outside temp). In short, the cabin getting air that is hotter than outside is very rare, but occasionally happens. It’s probably 25% cold, 75% outside temp, outside of when I get that random heat occurrence.

Would I take it to a professional and spend $1,000+ when I could do it myself in a few hours and only spend $100 in parts? No. But there comes a point when I run out of solutions and I may have to. Fixing things like this is something I usually enjoy when it isn’t an unsolvable puzzle like this has turned out to be.
 

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I am almost hesitant to say this because I have visions of you pulling your dash apart and not being able to use your car for weeks as a result, but it sounds like it's possibly a blend door or actuator. Or a vacuum line leak if these cars use vacuum operated blend doors, which I know was common in the past but I'm not sure about these cars; I haven't torn the dash apart on my car to find out.

I stand by my recommendation of using a professional here. These things are difficult to troubleshoot and, if it is an actuator issue, a royal pain to do.
 

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Discussion Starter · #7 ·
I am almost hesitant to say this because I have visions of you pulling your dash apart and not being able to use your car for weeks as a result, but it sounds like it's possibly a blend door or actuator. Or a vacuum line leak if these cars use vacuum operated blend doors, which I know was common in the past but I'm not sure about these cars; I haven't torn the dash apart on my car to find out.

I stand by my recommendation of using a professional here. These things are difficult to troubleshoot and, if it is an actuator issue, a royal pain to do.
Is there any way to somewhat diagnose this as the cause without tearing my dash apart?
 

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Is there any way to somewhat diagnose this as the cause without tearing my dash apart?
yep.....when selecting floor, vent, or defrost positions....does the air blow from the appropriate selected vents...this does not determine hot/ cold but let's you know that that part of the system is working..you can hear the doors move sometimes ..if yes..good....next
Have car fully warmed....select vents..not floor, not defrost.....it helps if it's as cool outside as it can be..
Don't select ac on or max air......select lowest temp setting you can have...usually 60, or low....air temp should be close to out side air temp. then select highest temp.....see if air temp from vents rises....go back and forth and see if it changes....if it does, your blend door is probably not the problem, nor are your electronics....if it's hot and stays hot, or, stays cool..then there's a problem with the door, door actuators , or electronics...
Understand this is testing the door movement....so, if it stays cool, and the ac is working properly, it should get cold...
This is what you have not given us:
1 high side readings
2 no mention of gunk, until now
3 positive statement of no leaks
4 what type of oil added, if any

in my opinion, you've now thrown a possible contamination issue into the pot....back to square one...

2
 

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Is there any way to somewhat diagnose this as the cause without tearing my dash apart?
I don't know. It's possible that there are ways to run diagnostics in VIDA but I just don't know. In some cars, I've been able to contort myself and look up behind and under the dash to watch blend door actuators (my old Porsche 944, for example) but I am not sure what is available for the S60 P3 cars in that regard.

One other potential thing to check is the evaporater drain tube. If that gets clogged, condensation that develops on the cold evaporater has nowhere to go and can lead to the evaporater icing up. If the evaporater ices up, the car will turn off the A/C to allow the evaporater to thaw. It's possible that the system is shutting off for that reason.

Troubleshooting these things is something that a shop can do much more efficiently because they work on these cars all day every day. I'm just a backyard wrench who enjoys fettling with his own cars and has been troubleshooting things long enough to have a really good diagnostic process. But the problem is that a good generic diagnostic process is ponderous and a bit slow because a lot of it is pausing, thinking about operational concepts, and working out how those concepts are implemented in a particular car. A professional who does this every day (like Tech on this forum) will have more specific knowledge about this car and will not need to move as slowly through a generic diagnostic as someone like me does. A professional will also have experience pulling parts and have developed tricks for dealing with difficult areas so that what takes a pro an hour may take me an entire afternoon. Or a pro might know to take extra care with a fragile clip that I don't know about and end up snapping, leaving me to wait another week for delivery of an extra part I have to buy because I broke that little clip.

If you're really interested in running this yourself, that's fine. I completely understand the desire to do what one can on one's own; I enjoy a good project where I can learn something as well. I just keep recommending a professional here because it looks like this is your daily driver and going weeks without air conditioning in Texas seems like hell.
 

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Have car fully warmed....select vents..not floor, not defrost.....it helps if it's as cool outside as it can be..
Don't select ac on or max air......select lowest temp setting you can have...usually 60, or low....air temp should be close to out side air temp. then select highest temp.....see if air temp from vents rises....go back and forth and see if it changes....if it does, your blend door is probably not the problem, nor are your electronics....
If it's a vacuum operated blend door, it's possible for it to work at idle (when the engine is running a high vacuum) but not as well at speed if there is a slight vacuum leak.
 

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Discussion Starter · #11 ·
Is there any way to somewhat diagnose this as the cause without tearing my dash apart?
yep.....when selecting floor, vent, or defrost positions....does the air blow from the appropriate selected vents...this does not determine hot/ cold but let's you know that that part of the system is working..you can hear the doors move sometimes ..if yes..good....next
Have car fully warmed....select vents..not floor, not defrost.....it helps if it's as cool outside as it can be..
Don't select ac on or max air......select lowest temp setting you can have...usually 60, or low....air temp should be close to out side air temp. then select highest temp.....see if air temp from vents rises....go back and forth and see if it changes....if it does, your blend door is probably not the problem, nor are your electronics....if it's hot and stays hot, or, stays cool..then there's a problem with the door, door actuators , or electronics...
Understand this is testing the door movement....so, if it stays cool, and the ac is working properly, it should get cold...
This is what you have not given us:
1 high side readings
2 no mention of gunk, until now
3 positive statement of no leaks
4 what type of oil added, if any

in my opinion, you've now thrown a possible contamination issue into the pot....back to square one...

2
Based on the diagnostic process, I doubt this is the issue. But I’ll try all steps when it cools down tonight, including idling and driving. High pressure side is 235. The “gunk” is probably just leftover sealing agent from some AC Pro kit that someone used before I owned it. No leaks confirmed after using UV Dye through the system. No oil added as of yet.
 

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If it's a vacuum operated blend door, it's possible for it to work at idle (when the engine is running a high vacuum) but not as well at speed if there is a slight vacuum leak.
that's why i preface pretty much everything i say with " probably ". He can still run the same evaluation while driving if he feels that could be goin on. Most cars today use actuators controlled by the selections made on the ac panel coordinated through the ecu. There are very few cables and vacuum hoses left. BBUUUTTT, maybe these volvo's still operate that way.
so he asked for a way a saturday mechanic can run a test , i gave him one......
 

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If it's a vacuum operated blend door, it's possible for it to work at idle (when the engine is running a high vacuum) but not as well at speed if there is a slight vacuum leak.
that's why i preface pretty much everything i say with " probably ". He can still run the same evaluation while driving if he feels that could be goin on. Most cars today use actuators controlled by the selections made on the ac panel coordinated through the ecu. There are very few cables and vacuum hoses left. BBUUUTTT, maybe these volvo's still operate that way.
so he asked for a way a saturday mechanic can run a test , i gave him one......
Good points all. Just wanted to mention the limitation.

I've seen electronic controls activate vacuum valves to control blend doors in some cars, though I agree that it seems likely things are going fully electric these days with how inexpensive stepper motors and potentiometers are these days.

One reason I considered a blend door was because he says the blower sound changes when the A/C stops.

Either way, cheers! You've given lots of good help and it's a pleasure to share a thread with you.
 

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Based on the diagnostic process, I doubt this is the issue. But I’ll try all steps when it cools down tonight, including idling and driving. High pressure side is 235. The “gunk” is probably just leftover sealing agent from some AC Pro kit that someone used before I owned it. No leaks confirmed after using UV Dye through the system. No oil added as of yet.
ok...so any left over gunk could have accumulated, once again, in the expansion valve. I am more experienced with orifice tubes than expansion valves . A clogged or dirty orifice tube usually causes abnormal low side , low pressure readings with accompanying abnormal high side high readings.....except that the low pressure switch and / or high pressure switch ( if it has one) will cause the system to cycle off and on....which can mimic low refrigerant charge......you see where i'm going with this....it's a process and i keep saying this, that needs to be followed methodically....what's my point?
that the gunk needs to be removed from the system components if in fact any gunk remains . You can't just disregard contamination as irrelevant even if it was leak seal designed for ac ( supposedly) i don't like 'em...you said the valve was all gunked up, who knows how it's affected everything else....., the system needs to be clean, pulled down, moisture removed, recharged again.
If it was my car, and i removed an expansion valve covered in gunk after i put in leak sealant....i would reluctantly flush the system as best i could...replace the receiver/ drier......i might try to get by with the condenser, maybe..and then kick myself later for not replacing it.......i know what you want to hear....but to me, you're back to square one again..

i should add, because i'm just a saturday mechanic with no fancy testing machines, when i have issues like yours, i bypass the low and high pressure switches to run my tests. i don't run 'em long, just long enough to see what my pressures are .
once again, a properly operating system,technically, does not need these switches, they are there for protection.
Your saying now that you see 235/65...and those readings will vary with outside temp and humidity....so you need a chart to show what's normal for your car. Your low side is high, i believe, i do not know what is normal for your car.
the best way to check for leaks is to draw the system down with a suitable vacuum pump, close the system off and let it sit for ,well, let's say an hour...see if the vacuum holds. assuming your testing hoses and gauges are not leaking, valves not leaking, etc., it should hold the vacuum. if it doesn't, you have a leak.
 

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Discussion Starter · #15 ·
Based on the diagnostic process, I doubt this is the issue. But I’ll try all steps when it cools down tonight, including idling and driving. High pressure side is 235. The “gunk” is probably just leftover sealing agent from some AC Pro kit that someone used before I owned it. No leaks confirmed after using UV Dye through the system. No oil added as of yet.
ok...so any left over gunk could have accumulated, once again, in the expansion valve. I am more experienced with orifice tubes than expansion valves . A clogged or dirty orifice tube usually causes abnormal low side , low pressure readings with accompanying abnormal high side high readings.....except that the low pressure switch and / or high pressure switch ( if it has one) will cause the system to cycle off and on....which can mimic low refrigerant charge......you see where i'm going with this....it's a process and i keep saying this, that needs to be followed methodically....what's my point?
that the gunk needs to be removed from the system components if in fact any gunk remains . You can't just disregard contamination as irrelevant even if it was leak seal designed for ac ( supposedly) i don't like 'em...you said the valve was all gunked up, who knows how it's affected everything else....., the system needs to be clean, pulled down, moisture removed, recharged again.
If it was my car, and i removed an expansion valve covered in gunk after i put in leak sealant....i would reluctantly flush the system as best i could...replace the receiver/ drier......i might try to get by with the condenser, maybe..and then kick myself later for not replacing it.......i know what you want to hear....but to me, you're back to square one again..

i should add, because i'm just a saturday mechanic with no fancy testing machines, when i have issues like yours, i bypass the low and high pressure switches to run my tests. i don't run 'em long, just long enough to see what my pressures are .
once again, a properly operating system,technically, does not need these switches, they are there for protection.
Your saying now that you see 235/65...and those readings will vary with outside temp and humidity....so you need a chart to show what's normal for your car. Your low side is high, i believe, i do not know what is normal for your car.
the best way to check for leaks is to draw the system down with a suitable vacuum pump, close the system off and let it sit for ,well, let's say an hour...see if the vacuum holds. assuming your testing hoses and gauges are not leaking, valves not leaking, etc., it should hold the vacuum. if it doesn't, you have a leak.
System was flushed as good as possible when condenser/drier and shortly after expansion valve was replaced.
 

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i just got in, tired....so....tomorrow......but if everything is as you say it is and still can't pull a lower reading on the low side.....maybe compressor issues
it's hard to do this over the internet.....
 

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Discussion Starter · #17 ·
i just got in, tired....so....tomorrow......but if everything is as you say it is and still can't pull a lower reading on the low side.....maybe compressor issues
it's hard to do this over the internet.....
Passed the blender test. All functions in the testing process worked correctly. Might add sometimes when I start my car, there is a very slight mildew/old smell, but that could just be the filter as I haven’t changed it yet and am sitting at 120k miles. I’ve only had it for 10k miles.
 

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Check the evaporator drain next.
 

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morning....ok......i'm gonna look over my 2012 s60 today......i'm gonna put my gauges on it and see what pressures i'm running with a normal operating ac system on my t5.......also, you can check ,and i'll check to see if it's possible to actually feel the inlet and outlet lines to the evaporator ( something tells me no)......they should be close to the same temp......this is old school stuff...
......
 

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fyi...2012 volvo s60, t5.......82 degrees F, 52% humidity outside.....properly operating ac system..53,000 miles
car off..static refrigerant pressure..110psi.
car on- idle......temp. selection- low......fan- high......cabin air selection-recirc.
air duct temp - 47 degrees, center duct.
high side refrigerant port pressure- 175 psi.
AND no cycling of the compressor......

as a side observation, with ac off, temp selected high, my cabin air temp measured 138 degrees F

Also, it appears volvo wants me to keep my hands off as the low pressure port is supposedly hidden below the coolant tank, too much work for me.......and...the evaporator lines seem to be untouchable.
I'd say, if your hi side is 235 at idle, that's way too high....
sorry, no low side readings....hope this can give you some guidelines
 
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