I have an engine speed related whine-most noticeable on tickover and when revving while stationary, but less so while driving (drowned out by the other normal noises).

IID tool shows between 13.2 and 15 volts while driving, mostly at 14.7. No other symptoms.

Looks like the original is still on the car.

I assume a Denso is the only one to get?

Thanks all.

I would think it's more likely to be one of the belt runners or tensioner, take the belt off and spin them, if they feel/sound rough you know that's the one...

You can briefly run the engine and if it still makes the noise you have ruled out a lot of things..!! Pete

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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
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Good idea

If it's a grubling bearing then it probably wouldn't show on IID sir... As Above, remove the aux belt and run it briefly...

Thanks. Not a grumbling sound, just a whine that’s quite high pitched.

Just to update, I changed the alternator today and the whine is gone.

Normal, quiet service is resumed.