E39 squealing like a pig

[BliarOut]

When it's very cold my E39 squeals like a bh... It *sounds* like it's coming from inside the inlet manifold rather than the inlet tract itself. Is there anything in there that could be causing the squeal?

It increases under load such as when the PAS is in use and slowly goes away to almost nothing when she's hot.

I'd rather have an idea what I'm looking for before I start pulling things apart

[sleep envy]

BliarOut said:

I'd rather have an idea what I'm looking for before I start pulling things apart

two of these



and a pair of these



yeee and indeed haw

[BliarOut]

Duelling banjos'? I think I'd probably have noticed them in the engine bay TBH

[Pickled Piper]

Belts and tensioner are the obvious places to start. Then ancillaries;alternator, PAS etc.

pp

[BliarOut]

It sounds like a slipping belt... But isn't. I'm wondering if it could be something to do with the idle control valve?