Ever since I got my Clio a few months ago it's been making a sort of squealing sound when I'm letting the clutch pedal out at a certain RPM. If I'm moving off at a lower RPM (such as for downhill starts or just flat starts) it will not make the noise. It also does not make the noise if I move off at a higher RPM (e.g. for uphill starts); it seems to be somewhere in the middle, between low and higher RPM. The clutch does not seem to be slipping or any signs of wearing other than this sound; the car moves off and engages every gear perfectly fine, it's just an annoyance more than anything. It's been an ongoing problem for months and I never bothered doing anything to it or checking it out as this is my first car and I'm not looking to put any/much money into repairs. Over the months the problem does not seem to have gotten any more severe or frequent than it was when I got it. Any idea what this is? Also would the car pass UK MOT test with this noise? Thanks
My bet is... the clutch disk (the friction part) happens to vibrate at a frequency that coincides with that particular engine RPM, and is barely free enough to vibrate with the clutch disengaged. If I'm correct, it's nothing to worry about - only an annoyance, and shouldn't shorten the life of the clutch.