If it's making the telltale buzzing/droning noise that old dirty fans make, the best solution is to replace the fan....
However, when that's not an option, I've gotten significantly more life out of old fans by liberally apply lubricant to them. To do any good you have to get it right onto the bushing, which is usually accessible by peeling back the sticker on top of the fan, exposing a hole over the bushing. Drip some oil in there, spin the fan manually to work it in, and apply more if need be. (I use this for lube) Finally, attempt to replace the sticker and power the computer back on.
In my experience, this lets a fan operate quietly for at least a few more months. Usually this is a pretty simple procedure, but some people may not be comfortable doing it, and the usual disclaimers apply (attempt at your own risk, ect.).![]()
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