Volvo: 2001 V70 A/C, trip trip, freon

Question
Hi,  My 2001 V70 A/C seems to be blowing intermittantly cold.  From what I have noticed the problem is usually worse when the outside temperatures are really high (upper 80sF or higher) and the car is idling.  Under these circumstances after just a minute or two it tends to blow hot air.  Sometimes it is OK, and usually when moving the air is cold.  I have noticed that turning the A/C off for a few minutes then back on seems to fix the problem.  I have checked the refrigerant and pressures seem fine, but I haven't been able to check at a time when the a/c is blowing hot.

My thought is that the condenser is getting "heat soaked" and unable to perform adequately.  Does this make sense?  What could cause this and how to fix?  What else should I look at?  I'm trying to avoid taking to a shop because I hate to incur a huge bill without something I can try and try to understand ahead of time.

THANKS,
TRIP

Answer
Trip,
The system works very poorly when the system is just slightly low on freon. First step is to evacuate and recharge with the amount shown on the under hood tag. If that don't prove to help. Then check to make sure that the compressor is always getting power. Compressors are know to fail. It will get power and not be on, sometimes due to the overheat sensor or at times the clutch.