Weird noise

[DWRIGHT]

Here’s something different on my 2007 XK 4.2.When I start it up from cold there is a weird noise coming from around the front of the engine compartment,the nearest I can describe it as is a note played on a recorder or flute not a screech as if a belt is slipping or a bearing noise.I have been working on cars for over 50yrs but I’ve never heard this one before any ideas would be gratefully received!By the way once it warms up or I drive it for a while it stops.

[steve_m]

Not the most obvious culprit but it did happen to somebody: