What the hell is this whizzing noise !!!???

[NovaSpen]

Hey people, i have had this noise coming from my engine and i swear it is'nt normal. When i rev the engine i get this whizzing noise, then when im goin along and put my foot down it starts again, but it especially loves it when im slowing down, thats when it makes the most noise. I took it to the garage where i have it MOT'd and they said it was the alternator so i went today to an electrical place for cars and he put this reconditioned alternator in and guess what, it was EXACTLY the same, even though when the alternator was off then i reved it, it was absolutely perfect, WTF!? Someone please shed some light on this as i have no idea what it is.
Cheers
Spen

[burgo]

you might find the alternator belt is to tight mate

[Donova]

know the feeling,and the noise,mine makes a weezing on tickover, took the belt off and its like a rolls-royce! I thought it was the bearing. :?

[Adam]

know the feeling,and the noise,mine makes a weezing on tickover, took the belt off and its like a rolls-royce! I thought it was the bearing. :?
If you run the belt too tight for a while then it will wear the alternator bearings out.
Loosen the belt, just make sure its not slipping, it don't need to be mega tight.

[5toprjepog]

Between the alternator and upper belt with 10 kgs of pressure on it should move about 5 mm either way

[Aragorn]

try and turn the engine using the alternator pulley - if engine turns belt is tight enough, if the pulley slips its not

[NovaSpen]

Ok changed the fan belt 2day, noise has got a bit quieter but not gone. Loosened it a bit and it made the same noise but had a rattle. Took the belt off and revved it and the whizzing went away. What the hell is it?
The guy at the garage reckons its the normal noise that the alternator makes when it is charging LOLOL WTF!

[5toprjepog]

I think it maybe more serious if you don what everyone has said maybe a bearing has gone and is screaming