Howling sound coming from inside

[Helmir09]

Hi everyone, i have been experiencing this howling sound hearing from inside the car. It comes and goes. Sometimes when moving and at time during stationary as well.
Can anyone who have experience such sounds enlighten me on what could the cause possibly be? Im driving a 2011 520i

Thank you!

 

[rssid]

kids or wife ?

 

[Helmir09]

Luckily non of the above but it is very annoying to hear.

 

[Citizen69]

is it the radiator fan that is running at high speed? If so, could be thermostat rosak

 

[Helmir09]

It’s not the fan. Thermostat also just replaced. But thank you for sharing

 

[Waihoong]

It happens to my 318i!!! Kinda stuck and dunno what to do. Got myself a new G20 in Aug 2024 and it's making this howling sound when the car is slowing down or even stopped.

What was done:
Went in 3 times to dealer. Took out the brakes and wheels - no issue found.
Suspected AC expansion valve - replaced the valve, top-up refrigerant

None of those help. Anyone experienced this? Heard of this?
The dealership has no idea what's wrong ....any help is appreciated