Problem with heatsink fan

Lately my CPU heatsink fan has been acting weird. Every 30 seconds or so, it slows down for a few seconds and then speeds back up again. It never used to do this until recently. Is it time to replace it? I've owned this heatsink fan for 2 1/2 years.

 

sounds like the fan is dieing ... either that or the header on the mobo is going bad

 

What's the header on the motherboard?

 

might be a mobo's feature.. to make your pc more silent..

 

The fan blades could be full of dust,you would not believe how must dust can cake up on the blades. Fans are check,get a new one and there quieter too.

 

Not check I meant cheap.

 

it's where you connect your fans power cord to the mobo ... it might have blown but I doubt that .. if giving it a good dusting with compressed air doesn't fix it, the only thing to do is replace it