'95 Auto Disco whistling sound from under the hood

Oreet, this is my first post! Had a J reg manual before, loved it, absolutely bomb proof, got this N plate auto after few years without a disco. Dont know a great deal about engines but know that the whistling sound I can hear from under the hood shouldnt be there. Tried spraying WD, sound goes for a while then returns - could it be shot bearings somewhere, seems to be coming from around the drive belt? Anyone any thoughts?

search out:
the penny trick & replacing the tensioner bearing

Its possibly a Polish car wash attendant working away and enjoying himself...

Could be many things seriously, alternator bearings, belt tensioner bearing, water pump.. try the old dodge of listening using a long screw driver pressed against your ear ant touching metalwork near to the noise to try and determine where its loadest... works, but BE CAREFUL, spinning bits hurt.