MG4 luxury HUMS loud when cold at 35mph+

S

sava1e

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Location
Amsterdam, The Netherlands
Driving
MG4 Luxury
In the Netherlands it's now freezing two mornings in a row. The first 5 to 10 minutes the car makes a very loud humming noise when driving 35mph+. The tone and volume differs when increasing speed. When the car is heated after a longer drive / in the afternoon the humming noise totally disappears.
Anyone else having this problem / knows what this can be?

a recording here: (humming sounds starts from 0.07)
 
Could it be that the Active Grill System is shut when the car is cold and it's the air vibrating the shutters. When the weather/car's warmed up the shutters are open allowing the air to flow freely.

Might be worth checking there isn't anything stopping one or more of the shutters closing fully.
 
bottom.jpeg
shutters.jpeg

@NLMGSAN
@Ian Key

The bottom looks ok to me?
The shutters were closed normally when I checkled the car. Strangely enough they opened as soon as I pressed the brake pedal. After a minute or two the radiator? was full of ice because it was freezing. Not sure if it's related / can cause that strange sound?
I also did a drive by: outside the car the humming noise is not audible.
I will also let my tires checked, but I don't get why the noise would disappears when it gets warmer.
 
Last edited:
Regarding the rear undertray ... take a photo from in front of the rear wheels looking backwards. It's the leading edge of the rear undertray that's usually the issue. :)
 
We have an air to air A/C heat pump for the house , when its very cold and humid the air rushing through the outside unit causes the " radiator " section to ice up, it then starts running badly and makes a humming straining noise with the compressor. We have to switch it off and let it defrost then its fine.
I'm suspecting its the same for the unit in the car?🥶
 
sava1e said:
Ok will make another one tomorrow!
Ice on the radiator seems to be related... If there is no ice, there is no strange hum and visa versa.
I don't get why the shutters open when it's -2 outside.
Click to expand...
To be honoust, it was -5 this morning and I did not have a humming radiator. But I have no clue whether the shutters were open or not.
 

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