2008 Volvo C30 Air Conditioning

[paul08C30]

I have a fault with my 2008 Volvo C30 Air conditioning and could really do with some advice.

At the end of last summer the air conditioning stopped working. I didn't bother looking into it until this spring. I put my gauges on the system and the pressure appeared to be low, the static pressure was around 10 psi on both sides. So I got the system recharged at my local garage but it still didn't work. When I put my gauges on, the static pressure was around 50 psi at approx 12 C. With the engine running, air con on max and recirculating, the pump clutch is engaged and turning correctly. However, with my gauges still attached, the pressure on the low side was between 25 and 30 psi but on the high side it was around 100 psi. At this point I decided to get a replacement pump. So I sourced a guaranteed used unit, had the system evacuated and swapped the pump out. I then had the system recharged at a different shop, just in case, but the result is exactly the same, 25-30 psi on the low side and 100 psi on the high side, with no cold flow in the cabin. Any advice would be gratefully appreciated. Thanks. 

[tbirdtbird]

Is it known if either shop weighed in the charge?
Was the leak ever found?

[paul08C30]

Is it known if either shop weighed in the charge?
Was the leak ever found?

Yes, both weighed it in.

No leak was found. The system seems to hold both a vacuum and pressure without issue.

[paul08C30]

The only thing between the compressor and the high pressure valve is the condenser. Is it possible that the condenser could be partially blocked internally?

[Cusser]

Are you SURE that you're adding enough refrigerant???

[paul08C30]

Are you SURE that you're adding enough refrigerant???

If I put more refrigerant in, the compressor then cycles, with the low pressure going high.

[JohnHere]

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

[DetroitAC]

Your pressures sound reasonable for an ambient of 12C, have you had a chance to try at current summer temperatures? Where are you located, and what is your ambient?

Based on only what you have said so far, maybe it's a temperature blend door issue in your HVAC? But please try in hotter weather at full blower, windows down, idle and engine revved up to maybe 2000 RPM.

[paul08C30]

Your pressures sound reasonable for an ambient of 12C, have you had a chance to try at current summer temperatures? Where are you located, and what is your ambient?

Based on only what you have said so far, maybe it's a temperature blend door issue in your HVAC? But please try in hotter weather at full blower, windows down, idle and engine revved up to maybe 2000 RPM.

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.

The only way I've been able to get cold air through the vents (as low as -0.6 C) and the gauges to read 25-30 psi on the low side with 225 psi on the high is to over-charge the system and bypass the pressure switch (although I've not done this with the replacement pump). But when I switched the engine off the static pressures were up to what would have been suitable for 30 C and not the 22 C ambient temperature that it was at that time. And with the switch reconnected the compressor cycles on and off.

[JohnHere]

Good catch, DetroitAC. Being in the USA, I don't normally think in degrees Celsius. A temperature of only 12 degrees C. (54 degrees F.) is far too low to be testing an A/C system and measuring pressures. I don't even consider doing that (outdoors, at least) until the ambient temperature reaches 24 degrees C. (75 degrees F.) or higher.