2008 Volvo C30 Air Conditioning

[paul08C30]

My sources specify the following for the 5-cylinder 2.5L engine: 19 ounces of R-134a and 6.8 ounces of PAG-46.

Yes, 535 grams (approx 19 ounches) was weighed in by both shops.

[tbirdtbird]

Static pressure at 22 C was just over 70 psi. But the running pressure was the same, 25-30 psi on the low side and 100 psi on the high side. Holding higher revs on the engine makes no difference.

As already called out, your testing temp is too low to be of any value.
22°C is 71°F. In a system with trouble we wait until we have at least 80F ambient, higher than that is better.
Not much is gonna happen at 70F.

Most ppl would not even consider the need for AC at 70F

When the units of measurement are mixed or SI, etc it can get confusing here in the USA

Please always post your actual hi and lo pressures, your vent temp, and the ambient, the RPM, and avoid phrases like "this new reading was less than the previous" and such like that

[paul08C30]

I've just been out and check everything again, best I can. Static pressure is approx 68 psi, at an ambient temperature of 19C (66F) (which is the same as my other car where the air con works fine). With engine running at 2000 rpm, pump is engaged, fan is running. Low side pressure reads 27-32 psi, High side reads 100 psi (if I block off the fan it goes up to 120 psi but no more). The pipe coming from the compressor to the condenser is hot to the touch, best reading I could get was 50C (122F). Pipe coming from the condenser is below body temperature but I couldn't get a reading. Same pipe enters the dryer and exits at much the same temperature. Where this pipe enters the bulkhead, which I assume is the expansion valve, the last 6 inches of pipe has ice on it, best measurement I could get was 1C (34F). return pipe from bulkhead (larger diameter) is around ambient temperature, but again I couldn't get a sensible measurement. Air temperature at the vents is approx 20C (68F). Any help would very much be appreciated. Thanks.

[paul08C30]

Static pressure at 22 C was just over 70 psi. But the running pressure was the same, 25-30 psi on the low side and 100 psi on the high side. Holding higher revs on the engine makes no difference.

As already called out, your testing temp is too low to be of any value.
22°C is 71°F. In a system with trouble we wait until we have at least 80F ambient, higher than that is better.
Not much is gonna happen at 70F.

Most ppl would not even consider the need for AC at 70F

When the units of measurement are mixed or SI, etc it can get confusing here in the USA

Please always post your actual hi and lo pressures, your vent temp, and the ambient, the RPM, and avoid phrases like "this new reading was less than the previous" and such like that

I appreciate what you are saying, but the humidity can be quite high here in the UK, so A/C is of value. And I can tell that it is definitely not working as my other car works just fine, and is clearly noticeable, even at these relatively low temperatures. However, I do appreciate yours and everyone's input. Thank you.

[tbirdtbird]

At ambients that low we are gonna have to let the heavy hitters here wrangle with this.
Did this car ever cool properly at 66F? Have to wonder if the other car has some type of special equipment on board to make it work.....

[JohnHere]

If you have ice on the high-pressure line six inches before the TXV, I'd say that there's some kind of restriction in the line just upstream of where the ice is beginning to form, causing evaporation to take place in the line itself before the refrigerant passes through the TXV into the evaporator. The HP line should be uniformly warm to hot up to its connection with the TXV.

[paul08C30]

At ambients that low we are gonna have to let the heavy hitters here wrangle with this.
Did this car ever cool properly at 66F? Have to wonder if the other car has some type of special equipment on board to make it work.....

Yes, it used to be ice cold, even at 66F. I'm not making this up, I promise.

[tbirdtbird]

That is good to hear, tho all I can think of is a greater possibility of slugging the comp at such a low ambient

[DetroitAC]

I think you might have a restriction in the liquid line, but maybe also just a stuck TXV, and upstream ice forms after a long time? Hard to say without seeing it in person. Water inside the system can also act like this, it'll build an ice plug right where the temperature change happens in the TXV.

My money is on jammed TXV, stuck at a small opening

[paul08C30]

If you have ice on the high-pressure line six inches before the TXV, I'd say that there's some kind of restriction in the line just upstream of where the ice is beginning to form, causing evaporation to take place in the line itself before the refrigerant passes through the TXV into the evaporator. The HP line should be uniformly warm to hot up to its connection with the TXV.

I like your diagnosis, thank you.