First of all I did take my car to a shop that specializes in HVAC. They checked out the A/C and found that it did not need refrigerant and was operating fine until for no reason the compressor shut down. They felt it was a bad sensor or ECU and suggested that I take it to a Volvo dealer to be checked out. I then took my car to a Volvo dealer in Cleveland and had a Volvo Master Technician check it out. He is the one that told me that the high temperature cutoff switch which is located inside the compressor is the problem. This switch or circut breaker is similar to the bimetal fuse used in hair dryers. Heat warps the bimetal strip to open the circuit. When it cools down it flattens the bimetal strip and makes contact to complete the circuit. These switches are only a last resort and intendend to protect your compressor if the low pressure switch does not shut down the compressor if you lose refrigenant. There is a good chance that the switch was set too low from day one and would have been replaced under warranty if I lived in a warm weather climate and the problem would have showed up earlier. All the external switches checked out and when the compressor cut off he told me that there was still power going into the A/C. He added that my compressor was not overheating however because of the high ambiant temperature it reached a temperature above the sensor setting. As far as me replacing some refrigerant with some oil charged refrigerant, since when has R-134 been considered harmful to the environment? Since my A/C is now starting to cut off at a lower ambiant temperature (85*) my guess is that either the high temperature cut off switch is getting worse or there is more friction causing more heat to build up in my compressor. Doesn't oil reduce friction thus reducing operation temperature? What do I have to lose? If it doesn't work I will have to replace the compressor anyway.