Strange Sound .... any ideas?

I have started to experience a strange sound from the engine bay on my Cabbie when I am either moving slowly or sat in rush hour traffic. It's hard to describe the sound - somewhere between a buzzer and a trumpet sound. It only lasts about 30 seconds and goes when I move on in traffic, but is quite alarming (excuse the pun!).

Anyone got any ideas what it might be?
Car has been recently serviced & beyond the sound there seems to be no other ill effects.

Cheers Rob

alternator belt slipping? is it a squeel? kind of hard without hearing it.

Known VW`s its the dam bearings in the rad fan motor! Ive gone through 3 of them!.. every time i go to the scrappys it s " Hi andy, is it a Mk2 fan motor again" lol

If it is what i had with one of my mk2's, it sounded like an elephant type noise, which is the bearings on the fan

Peddersgolf said

 it sounded like an elephant type noise

   Yea that's it!
How difficult is it to change these bearing or do I change the fan motor?

Thanks for the responses - Rob.

Best replacing the fan fella, simple job, 5 minutes to do  :wink:

Yeah and the MK2 is the same motor.. same bolt holes too. Cheap job..lol