Whirry noise on V8

[Hardy]

Alright, I'm on a mission to solve the mystery noise.

130,000 klm '99 RR 4.0
There is a whirry whiny noise that is only apparent at idle and fluctuates slightly with the revs at idle. Increase revs and noise disappears. It's been doing this since I got the car 55,000 klm ago.

When I do the screwdriver to the ear test, the alternator emits the highest indication as the source, although I haven't been able to ear test the water pump with engine running.
Yesterday I had new bearings and regulator put into the alternator, the noise is still there.

I've already replaced the idler pulley and the car has a new serpentine belt.
It's nothing inside the engine as noise is not present with serpentine belt detatched. It's not the air-con either nor steering pump.
I'm reluctant to replace the water pump as there's no fluid loss and the fan seems pretty tight on it's shaft.


Any tips or clues? Anyone got a spare alternator I could borrow for process of elimination?

Thanks,
Hardy

[rsrichie]

i recently replaced my alternator the new one has a wir that is mostly there but sometimes goes away. I also recently replaced the P/S pump which made no differance so my guess it is the dodgy original alternators but hey who knows if its not one thing it seems to be another with these beasts.