2011 XC60 AC Problems Only working when driving fast highwy

docperio44 · Post by **docperio44** » 24 Jan 2015, 05:58

Hi All,

First time poster here... but I'm having a problem that no mechanic has been able to properly diagnose. I've been told I need a new compressor and the works to the tune of $2k. I don't have it.

The AC blows cold only with consistent, long driving at decent speeds. Works well on highway. It stops working with any stop and go driving. With the AC on in park/nuetral, sometimes (not always), there is a humming/buzzing that gets stronger with RPMs.

I find it hard to believe the compressor is the problem. Usually they work or they don't. I'm wondering if this is related to the clutch gap posts. https://www.matthewsvolvosite.com/downlo ... AC-Fix.pdf

Any help would be greatly appreciated.

Post by **jimmy57** » 24 Jan 2015, 10:24

The compressor on that model is a variable displacement compressor. It does have a clutch but it doesn't cycle on an off and clutch wear is nil so gap issue doesn't affect it.
There is a solenoid on compressor that controls the displacement and those can stick but you mention the compressor being noisy. Does the cooling fan run? If the cooling fan is not running then it will only cool at speeds where the moving of the vehicle is forcing air through condenser so A/C works. No fan operation will raise high side pressure and compressor can be noisy for that reason.
Or it needs a compressor.

Post by **oragex** » 24 Jan 2015, 11:03

I am no expert in more recent vehicles, but if the a/c works only at higher driving speeds, it could be because the a/c condenser that is located in front of the vehicle (near the radiator) gets more air flow that helps it eliminate better the heat (heat is extracted from the refrigerant when it's compressed to be cooled down). in other words, the condenser needs a steady air flow to evacuate the heat and therefore to be able to cool down the refrigerant. otherwise the refrigerant can't cool and the a/c cannot blow cold air.

the cooling fan located behind the front radiator must be always turning (at a lower speed) when the a/c is engaged. check in the first place the fan turns when the a/c button is on.

as a side note, a used compressor bought off Ebay should be fine, and should come at a fraction of the price of a new one

docperio44 · Post by **docperio44** » 24 Jan 2015, 12:42

Thanks to both.

My mechanic checked the fans and brought them to max speed. he claims they are both good.

What can I expect for install of a new compressor$$ ? It seems complex

Post by **jimmy57** » 24 Jan 2015, 17:47

Rockauto has the OE brand compressor (Valeo) sold by GPD for around $450 shipped. You'll need a receiver/drier insert for around $20 and also some compressor oil that you can get in an auto store for $10. The compressor is not hard to change on that vehicle as it is front top item on engine. The receiver/drier insert is not too hard either.

Post by **oragex** » 25 Jan 2015, 09:04

Also, I suspect a refrigerant pressure check has already been performed?

docperio44 · Post by **docperio44** » 27 Jan 2015, 05:44

Yes, it has. I check it myself and it was high. It's since been flushed and recharged. I'm going to keep monitoring.

Post by **jimmy57** » 27 Jan 2015, 06:23

Low side was high?

With a variable displacement compressor low displacement gives you low side and high side pressures that are little different. In 85 degree weather with full charge the low side would be 105 psi and high side 120 with no cooling if compressor was stuck in lowest displacement position.

docperio44 · Post by **docperio44** » 29 Jan 2015, 05:28

According to my mechanic, the pressures on high and low equalize while compressor is engaged. He wants me to take it to an Auto AC specialist to check expansion valve and dryer.

Any thoughts?

Cadelane1 · Post by **Cadelane1** » 09 Aug 2021, 17:26

Where did you end up on this? My 2011 XC60 is doing the same thing. Low side reads high 120+psi and cooling varies with ambient temperature. If it is an overcast day it will cool even in metro driving same ones Highway no matter the temp; But only (and always) for a Short duration. If I’m replacing the control valve do I need to evacuate the system?

Thank you in advance