Somebody on xo had the same symptoms very recently. Turned out to be the harmonic balancer. Aka crank pulley.

Apparently those are made from two steel parts with rubber sandwich in the middle. If they start to delaminate, they will chirp/squeak and more when warm than cold.

In my collection of things I have a spare from I think an M62 motor. They are stupid expensive I would be able to sell a lot cheaper if I can find it.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)