high pitch noise at idle

[mokmok]

Hi,

I've waited a long time before posting about this problem trying to fix it on my own but now i'm at a dead end and im open to pretty much any advice,

I have a 2007 hatch and when the engine is warmed up and i'm stopped at idle for about a minute I get a high pitch noise that comes from the engine bay. Ive tried to film it (http://www.youtube.com/watch?v=vTiOPe6qmAg), without much success.. It sounds like a vacuum leak but even when I sprayed starter fluid on the vacuum lines it didn't affect anything ...the car tries to stall and the engine shakes in a way i dont really like

Then when the radiator fan comes on the idle goes up a bit and the noise disappears. As soon as the fan shuts down it starts again

I look foward to your advice

thanks