MG4 SR rear axle noise

[Fernandnaudin]

Hello
I'm a french recent owner of a MG4 SR phase 2.
I've got a problem.
Immediately after leaving the concession, I noticed a muffled noise coming from the rear axle.
Initially I thought it was coming from the tyres, but the noise is not permanent, occurring at idle up to 70km/h.
This hum-like resonance noise occurs mainly on rough roads with a grainy surface.
A bit like the sound of a shock absorber compressing at the slightest irregularity.
After 2000km the noise is still just as bad.
I've searched a bit in France and on this forum but I haven't found a solution. Have you ever heard of this problem and if so with a solution?

This low-speed hum is very annoying.
Thank you for your help

 

[Buster72]

I have a 6 months old SE SR and I have not heard of that. But I would definitely query it with the dealer you bought the car from if you are not happy. Best of luck.

 

[Fernandnaudin]

He's already looked at the car on a lift, but nothing obvious... Thanks for jour answer!

 

[Torryhun]

He's already looked at the car on a lift, but nothing obvious... Thanks for jour answer!

Has he taken the car out on the road to hear the noise for himself? Maybe be easier to identify!!

 

[Fernandnaudin]

Has he taken the car out on the road to hear the noise for himself? Maybe be easier to identify!!

Yes he did, but can't identify where from the rear axle.
Not the tyres for him.
But It's like the sound of shock absorbers compressing over the slightest irregularity.
Maybe a problem with a Silent block?

 

[agy]

i too
from italy
from 1st moment car was orrible. Vibration front and rear. Changed tyres 3 times and with complete alu. But still present, less.
between 100 and 130 kmh top vibration. but not the same, for example to go to work at morning nothing and evening yes, today morning yes. I hear this similar experience at 50 kmh in street top at 80% so the suspension work a little
i think problem with axels, motor, and support in suspension.
my original tyres contintenal was all defected

 

[cyberster]

i too
from italy
from 1st moment car was orrible. Vibration front and rear. Changed tyres 3 times and with complete alu. But still present, less.
between 100 and 130 kmh top vibration. but not the same, for example to go to work at morning nothing and evening yes, today morning yes. I hear this similar experience at 50 kmh in street top at 80% so the suspension work a little
i think problem with axels, motor, and support in suspension.
my original tyres contintenal was all defected

Yes some original tyres were defective and were replaced under warranty

Hello
I'm a french recent owner of a MG4 SR phase 2.
I've got a problem.
Immediately after leaving the concession, I noticed a muffled noise coming from the rear axle.
Initially I thought it was coming from the tyres, but the noise is not permanent, occurring at idle up to 70km/h.
This hum-like resonance noise occurs mainly on rough roads with a grainy surface.
A bit like the sound of a shock absorber compressing at the slightest irregularity.
After 2000km the noise is still just as bad.
I've searched a bit in France and on this forum but I haven't found a solution. Have you ever heard of this problem and if so with a solution?

This low-speed hum is very annoying.
Thank you for your help

Sounds like the rear axle gearbox. Back to MG

 

[agy]

No replaced for me

Seller Cisa 2000 Bologna doesn t want to replace

 

[Fernandnaudin]

Yes some original tyres were defective and were replaced under warranty

I've got conti both front and rear. But there's no nois from the front.
And on a manhole cover, for example, the sound is almost ten times louder than at the front.

You're probably right, I think there's something vibrating on the small irregularities in the road.
What's certain is that you can't hear anything from outside the vehicle.
Could it be a problem with the damping of the stabiliser bar?

 

[agy]

I can see suspension is very cheap. So minimun imperfection for tyres reflect to drive with vibrations. So i will try an experiment in the next days. The last than i put the car to an mg center

have you got comfort version? Software?

 

[Fernandnaudin]

have you got comfort version? Software?

Standard version phase 2 tyres 17'.

 

[PristDean]

If you can, have an independent garage do a health check on the car and highlight your issue to them. They should be able to produce a report which you can then use to evidence any issues found to your dealer.

 

[OriginalBigAl]

Jack up the car , left side and swap front wheel to rear and vise vesa, drive it for while to see if there,s a difference. Then do the same right hand side, if the anomaly transfers to the front then it could be wheel balance or a bad tyre, good luck. ps there's no jack or wrench in the boot!
Provide gateau pour votre voisin.

 

[Fernandnaudin]

Jack up the car , left side and swap front wheel to rear and vise vesa, drive it for while to see if there,s a difference. Then do the same right hand side, if the anomaly transfers to the front then it could be wheel balance or a bad tyre, good luck. ps there's no jack or wrench in the boot!
Provide gateau pour votre voisin.

Hello
I've tried the cross tire change (front left for rear right).
I didn't really believe in it and... I was right!
It's worse with probably a noise linked to discrete facets!
Even when giving cake to my neighbor!

 

[siteguru]

Hello
I've tried the cross tire change (front left for rear right).

I've not looked - is there a direction (rotation) indicator on the tyres? If yes then FL for RR would have those tyres rotating in the wrong direction.

 

[Fernandnaudin]

I've not looked - is there a direction (rotation) indicator on the tyres? If yes then FL for RR would have those tyres rotating in the wrong direction.

No on the Conti 17'

Here's

 

[agy]

it is not a problem to tyres. I changed
1. 4 tyres in original 17 alu
1. 4 new alu 16 and 4 tyers new
1. 4 tyres new 17

problem remained

from continental:
tyres are damage by dealer stocking
the other 12 tyres are new, ok

in all of these i changed 7 tyres center

i think car has a seriuos problem

 

[Fernandnaudin]

An admittedly unintended experiment in noise reduction.
I had to carry 5 x 60-liter bags of wood chips in the trunk.
Result: almost complete disappearance of resonance noise.
At worst, I'll just have to carry these 5 bags around all the time...
The car goes to MG next week, so I'm not too confident, but we'll see!

 

[siteguru]

That's still useful info to share with the service guys ... the extra weight will have taken up more of the suspension preload, plus increased load on the rear axle.

 

[Fernandnaudin]

I'm not sure whether this is related to weight, but rather to volume and sound attenuation capacity.
Each bag of pine bark weighs about 10kgs, so 50kgs in all.
I've already carried 2 bags of cement in the boot without any effect on sound attenuation.
With the bags of pine bark, the boot was filled to capacity, without weighing much in the end.
I'm pretty sure that the resonance takes place in the boot, but why?