Hi, my mane is Ron, and am the proud owner of a 2008 s40 Volvo. At start-up, the car's A/C seems fine for about the first 15 minutes and the ventilation system starts blowing warm to hot air. I have taken the car to my mechanic who hooks it up to his machine to see if a code would register. However, no code is produce so my mechanic checks the refrigerant and that too come back noted as full. He then checks the level of the manufacturer's recommended radiator fluid, and its level was full. My mechanic recommended that I take my car to an A//C mechanic specialist. Have any you experience the same or similar problems with your 2008's Volvo s40? If so, how did you resolve that problem? I would appreciate any feedback!
V/R
Ron

 

Sounds like this could be due to the compressor clutch having too large a gap. What happens is when the gap gets larger than say .8mm (spec is .3 to .4 or so) it slips a little and that starts heating up the clutch. after a while the heat causes the electromagnet to loose its gripping power and the clutch stops grabbing. Cool the clutch down, and it works again. Most shops will simply replace the AC compressor (clutch and all) but it is possible to reshim the clutch to bring the gap back into spec. This seems to line up to your symptoms - proper refridgerant pressure, no codes, works fine when first starting out or on a colder day...

 

+1 with mt6127. A simple reshim of the compressor clutch will fix it. Have the mechanic remove the compressor clutch face and remove one of the 3 different sized shims inside the clutch hub to bring the gap back into spec. It took me maybe 15 minutes on my 2005 T5.