I have strange issue in my XC60, The AC system works great if I am driving fiast, but if I get slow down in traffic, etc, the compressor stops and it doesn't cool anymore. I checked the gas and it at the correct pressure. Any ides what could be wrong?

 

What engine do you have?

If it's the 6cyl you have a variable displacement compressor, and a the displacement valve can go bad and cause poor ac performance. Google volvo compressor displacement valve

 

yes its 6 Cyl 3.2 AWD, Thanks for the tip.

 

I wonder how your air flow through the rad and condenser is.
You don't say that the car is over heating so the cooling fan is likely working but if you have restricted air flow the AC system may be shutting down due to pressures.

 

Yes car runs fine no overheat issues etc

 

I realized you said your issue happens with fast vs. slow driving.... But when you say the compressor stops, do you mean the system keeps blowing, just that the air starts to come out warm? And does this happen right away or after a few minutes of driving first?

If the AC actually works quite normally for first 10 mins or so of driving and then starts to blow warm as time goes on... the problem could be related to AC Compressor Clutch gap, which is easily repaired using the standard "shim" fix. I had that issue on my 2004 xc90 and fixed it in 15 minutes with tie wraps. AC is still blowing strong several thousand miles later. (search here or on youtube for "volvo shim fix" or "bread clip fix" for more info)

good luck...

 

What happens is it after few mins of slow traffic (ie engine under low revs) the the air coming out of the vents become warm instead of cool. if I start driving fast again, the air will start to become cool again.