Originally Posted by s_k

So have I andrei, so have I .
And now you're wondering why your fans are noisy, aren't you?

@ BD: The problem is that the fan blows air and dust through the vents.
The result is this:

Maybe this isn't the case in your case, but if you have the idea that there's not much air coming out of your laptop and it's blowing all the time, you probably have a carpet of dust in your laptop.
Eitherway, the dust on the fan itself, if it isn't a massive amount, won't do it much harm