yeah im here in the UK and mine does exactley what yours does! It worked fine in the summer, and i switched it on the other day, and noticed the compressor doing the same as yours.....i can only suggest that maybe it does this becasue of the cold outside temperature?? but when i did stop using the air con at the end of the summer i noticed the air not getting as cold as it once was and the compressor making a bit of a noise, so i would also go with it may need re-gassing.