2007 Volvo V50 a/c and radiator temp

2007 Volvo V50 Front Wheel Drive Automatic 17600 miles

a/c works then starts blowing hot air after about 45 minutes. You can here the compressor cycling off /on, like its low on freon.
Stop turn off engine, let set for 15 minutes + -.
Restart a/c works again. However, radiator temp goes up.