First time posting and have to start by saying thanks to everyone who's posted a "how to" - they've helped a lot!

I need help figuring out what could make this sound!?!? It started last night and was proceeded by a slight whining sound that quickly turned into this. I've had the car for about 3 months and it's always had the Vanos rattle and the rattle at start up but this is something completely different and sounds really, really, expensive.



bmw 4.4 - YouTube


I'm taking the drivers side valve cover off tomorrow and having a look at what I hope is not schrapnel - anyone have any ideas of what I should check or look at while I'm in there?



2001 X5 4.4 167K miles