It could cause damage. It depends on a few things, if you overclock a cpu then it will naturally get hotter. Did you use it at 166 fsb for a while? You could put it to 166 and then go into windows and try a few apps and then restart and go into the bios. In the bios there should be a pc heakth status menu of some sort and check the temp of the processor if it's 55 C or higher i would advise you to put it back although alot of people think that is fine to run it at that temperature. Though you can't fry your cpu really as it won't let you, if it got too hot then it will turn itself off i think. If you want to run your cpu at a faster speed to make it cooler you could by a better heatsink with heat spreading or use a water cooling system.