Can people with a M3 please do a test for me

[Tigermad]

My car is booked in for 3 weeks time. It seems after checking here and elsewhere the odd M3 has the humming all the time when stationery and some don’t. I would assume they would all do it if it was normal

 

[moodel_tree]

At a guess its just the heat pump cycling under certain conditions. I'm assuming that the car is completely silent if the heat pump is not in use, and the car only hums when it kicks in to do what it do