Whining noise as I rev up

[skippy1981]

My Mk2 focus makes a whining noise when I rev between 2-3.5 k rpm. Happens even when I'm not in gear or clutch is depressed. What is wierd is that it is intermittent.. doesn't always happen and when it does it usually goes away after driving for ten min.

It's not a power steering leak... although the pump did run try during a previous leak (fixed by garage) so maybe pump is damaged?

Any ideas what it could be? Almost 50k on the clock. Could it be drive belt? At idle there is no sound at all from the area around the belt though...

Youtube clip of the noise

[skippy1981]

The engine is the petrol 1.6 Duratec 99bhp. My Focus is a Mk2.5 facelift version from 2009.

Cam belt has never been changed, but the power steering pump was changed in the past which may have meant the fan belt got adjusted. I can't see anything wrong with the PS reservoir now, but maybe the PS pump or the belt are damaged?

The alternator... no smells from it at all, everything smells OK when revving. Later I'll try and listen and see if its a bit louder from there.

I ordered a cheap stethoscope on Amazon and it arrives Friday.

Thanks for your suggestions guys, much appricated!