My Peugeot is making a new noise from the engine bay. At idle it sounds like a gentle metal brushing on metal noise but as the revs climb towards 2000, there is a rushing of air through ducting noise too. Once above 2000 RPM it doesn't get any louder or change in tone. Dipping the clutch at speed and letting the revs drop makes the noise go quiet again, so it isn't speed related, just engine speed.

The car is just as gutless as usual and doesn't drive any differently to the last 6 years. What things should I be looking at?

"Dipping the clutch at speed and letting the revs drop makes the noise go quiet again, so it isn't speed related, just engine speed. "

to me, sounds like clutch release bearing,

Mmm. The noise is the same at any engine speed with the clutch pressed or the same engine speed in gear and driving. Would there not be a difference between the two if it were the clutch (genuine question, I know nothing about clutches!)

What pug is it ? diesel or petrol,if petrol 8valve or 16valve ?? and what year.

last time i heard a wooshing air noise, it was a split intercooler on my diesel van. However, that did keep putting it in safe mode, which youd probably notice!

Sorry, it's a 2006 Peugiot 107 petrol. I don't think it is air specifically but it sounds like the resonant panel noise of air ducting. I guess if could be a crank case breather or a bearing in say the water pump or alternator, but I've never diagnosed something like this before. All ideas are welcome.

I've had 2 pugs now with that kind of noise. If it goes away when you dip the clutch then it's something to do with that.

However the first one lasted ages with that problem and I've only had the second one three months so far

Pug release bearings are pretty puny and quite often they come loose from the fork. Usually to diagnose with the engine idling you can take hold of the fork if you move it by hand you can feel and hear a change in the noise.