Any ideas? Unexplained high pitched whistling noise ...

[willevans19]

Please help, any one any ideas?

a couple of weeks ago my ford fiesta edge started making these high pitched whistling noise, no effect on performance at all and no warning lights, even took it in for mot, mentioned it to the garage and it still passed fine, they said they couldn't hear it and didn't notice anything under the bonnet...

what im finding odd is there is no particular times when this seems to happen, i.e. its not always when accelerating, breaking or turning ?? it just seems to happen randomly, it could go for miles and miles with nothing then have a bad 5 minutes, then other times it will be bad as soon i set off in it and the noise will fade ... even got my friend who is a mechanic to come round the block with me to see if he had any ideas and of course at this time it was quiet as a mouse, next day going to  work i could see other drivers looking over at the car obviously hearing the noise , most of the time its not terribly loud, but can be sometimes.

 

please any ideas let me know its driving me mad

:)