V5 engine
 

Can anyone help?
I have a Golf Mk4 V5 estate 2000/X Auto.

Recently a noise has started from the rear of the engine. It's a sort of whiring, kind of very faint exhaust blowing coming from the rear of the engine on the left. It speeds up with engine, not road speed. It's not the manifold I've had the exhaust checked. One of the garages said that it's not the alternator pully bearing? although it does rattle a bit and one of the garages thought the noise from the alternator was travelling to the back and being amplified.

Three garages have had a look and nobody can pin point it as it does seem to cover a wide area to the rear of the engine. Also it's quite noticable in the car.

It's got worse over the last week or so, less intermittent and slightly louder (to give you an idea of obviousness - I couldn't sell it like this). I've been told to wait until it get's that bad that it either fails or can be pinpointed.

I'm worried it may go bang and leave me with massive repair bills. Does anyone know about this problem or have had it happen to them and sorted it?

Any ideas?

Thanks

Mat