If after 30 seconds it starts blowing cold air again then I suggest its nothing to worry about. Theres a superheat switch at the back of the compressor before the wire comes out and if the compressor is working too hard, it shuts down for a bit to cool down before coming back on. 8 years is a pretty long time to go for a car without a regas though I think... but if its still blowing cold air then it seems to be well sealed. The most common sign of it needing a regas is a compressor which clicks on and off every 10 seconds or so constantly....