In alt.home.repair, on Tue, 12 Dec 2017 04:36:26 -0000 (UTC), Arthur
Wood wrote:


You should not need a login to read that thread and download the videos.
http://www.bimmerfest.com/forums/attachment.php?attachmentid=730369&d=1513035084

Here's just an audio file:
http://www.bimmerfest.com/forums/attachment.php?attachmentid=730353&d=1513034666

It's hard for me to tell what the sound is, so,

Any chance the thermostat went bad and the coolant is boiling?