[Lucky]

Been keeping an eye on the water level since my last post as previous owner had filled the expansion tank to the very top, so syphoned it out until it was between low and high. I have used it a bit this week and temp gauge reads normal, doesnt change on boost etc, but every now and then it smells a bit 'radiatory' and if I pop the bonnet after a spirited drive there are bubbles in the expansion tank (like its boiling), though the level is still just below full. Does this sound normal?