MG4 Undertray dip/bulge

Leebeejeebee · Feb 4, 2025

siteguru said:
Given that there's a well-known fix for this, which is available under warranty, I really don't understand why some dealers are so intransigent.

Direct link to PDF of MG's Technical Bulletin about this issue. (Hosted on my website. HTTP link rather than HTTPS, so your browser may flag a warning). You could do worse than print this out and show it to your dealer - after all you have raised a customer concern about this.

View attachment 34523

Thanks for this, I'll give it a try.

DaevM · Feb 5, 2025

Got mine booked in for 1st service in a couple of weeks. Raised this with them in the middle of last year, a couple of months after purchase. Informed them when I booked it in it is now recognised as warranty work by MG ( thanks to this marvellous forum

) and asked if they'd like the part number so they can get it ordered in. They said no thanks, they'd wait until it's in for the service, take more pics ( which they've already done once - and it ain't got better in the meantime) and submit another request to MG for warranty assessment.
Well, excuse me. I was only trying to help

.

turntoport · Feb 7, 2025

Leebeejeebee said:
I asked about this in December when I took mine in for service - they said it's fine. I said I was concerned that it would be scooping in air which would then have nowhere to go and create drag - they said it wouldn't create any drag and refused to fix it. Surely this is just physics?

yep it's just physics: The air passing the underfloor tray is somewhat accelerated by the 'venturi' effect of the form passing over it (hence F1 racing teams using skirty ground-hugging car bodies - see Mercedes recent porpoising cars...), so the actual 'speed' of the air passing the body is somewhat greater than the vehicle's speed, say 1.35 times. On the 'plus' side, the boundary-layer adjacent the car underside is probably iro 10mm that far back, so the air in that layer will be moving more slowly than the ~ 1.35 x carspeed free stream. However, water spray, salt, pigeon heads/squirrel tails, dirt (and mass liquid water if you drive through a floody bit deep enough to reach the undertray) will be nicely ingested by your saic-mg motor/battery ram-air/water scoop. Any car 'tech', sales rep (or anyone else) who says otherwise is bullshitting/gaslighting you.

turntoport · Feb 7, 2025

tried to get my 2-yr (from day 1) bendy scoopy tray booked in today. Strewth, what a fight. Obfuscation, ignorance, unwillingness. 0/10 for post-sales customer service, SAIC MG. A very good vfm ev ruined by absolutely crap service.
May i ask you good folk which dealers have provided this fix, 'cause mine sure has no intention of ever doing it ...

David9448 · Feb 12, 2025

So had a look under my '23 SE LR this morning, and it looks as if I've got the beginnings of a bulge, 2nd service not due till August, bought the car end of last september and not registered with the local dealership yet, and too far to take it back to the dealership where I bought it, did try to get it registered over the phone, but they said no, register it when you get the service done.
So what d'you reckon my chances are at getting this done now? or do I have to wait until the thing is dragging along the ground, seems to me it would be a lot easier job to do now, than when it gets worse.
Perhaps I'll email MG customer service to see what they say, maybe they'll tell me to take it in and get it done, or maybe thats just wishful thinking?

ReintjeWA · Feb 12, 2025

David9448 said:
So had a look under my '23 SE LR this morning, and it looks as if I've got the beginnings of a bulge, 2nd service not due till August, bought the car end of last september and not registered with the local dealership yet, and too far to take it back to the dealership where I bought it, did try to get it registered over the phone, but they said no, register it when you get the service done.
So what d'you reckon my chances are at getting this done now? or do I have to wait until the thing is dragging along the ground, seems to me it would be a lot easier job to do now, than when it gets worse.
Perhaps I'll email MG customer service to see what they say, maybe they'll tell me to take it in and get it done, or maybe thats just wishful thinking?

View attachment 34732

I would definitely lodge the claim, so even if it takes a while to get fixed, you made MG aware of the fault as soon as possible. Here in Australia there is a specific contact form for warranty claims on the main MG website, perhaps that would be a good way to go? (If this is the same in the UK)

David9448 · Feb 12, 2025

Ok, thanks, I'll have a look for that.

siteguru · Feb 12, 2025

Just lodge the complaint with your dealer - either original or the one you're going to use for the service - and tell them you want the undertray fix done when the car is serviced.

The technical bulletin for the fix is TI-20231228-EH32- Rear Subframe lower guard to Battery Gap - CEE and you can find a PDF copy on my website. I'd suggest sending them a copy of this when raising your complaint/notification - that way they can't try and say they know nothing about it and that the bulge is a "characteristic".

David9448 · Feb 12, 2025

Thanks for the info @siteguru and yes I will do that, although my local dealership wants to charge me nearly £300 for the second service, so might have to shop around a bit.

DixieTGS · Feb 12, 2025

David9448 said:
So what d'you reckon my chances are at getting this done now? or do I have to wait until the thing is dragging along the ground, seems to me it would be a lot easier job to do now, than when it gets worse.

Mine looked pretty much the same as the photo in the bulletin and they did it without question when I showed them the bulletin. Yours doesnt look hugely different either from what I can see in your photo.

NLMGSAN · Feb 12, 2025

siteguru said:
Just lodge the complaint with your dealer - either original or the one you're going to use for the service - and tell them you want the undertray fix done when the car is serviced.

The technical bulletin for the fix is TI-20231228-EH32- Rear Subframe lower guard to Battery Gap - CEE and you can find a PDF copy on my website. I'd suggest sending them a copy of this when raising your complaint/notification - that way they can't try and say they know nothing about it and that the bulge is a "characteristic".

That bulletin comes from MG east and central EUROPE. Actually, it is a Hungarian based company. Could it be other parts of Europe or UK have different bulletins?

David9448 · Feb 12, 2025

DixieTGS said:
Mine looked pretty much the same as the photo in the bulletin and they did it without question when I showed them the bulletin. Yours doesnt look hugely different either from what I can see in your photo.

Thanks thats reassuring, depends on the dealership though I guess, I'll get that bulletin printed and pop in to my local dealer and see what they say, it's pretty obvious that it'd be an easier job to do now than it would be in August when the service is due, because it can only get worse with time.

siteguru · Feb 12, 2025

NLMGSAN said:
That bulletin comes from MG east and central EUROPE. Actually, it is a Hungarian based company. Could it be other parts of Europe or UK have different bulletins?

... and written in near-enough perfect English.

Why wasn't it written in French, or German, or even Hungarian? I'd be surprised if this wasn't universal, at least for the EU/UK.

NLMGSAN · Feb 12, 2025

siteguru said:
... and written in near-enough perfect English. Why wasn't it written in French, or German, or even Hungarian? I'd be surprised if this wasn't universal, at least for the EU/UK.

Because MG Benelux did not have it when this one was released.
They do have it now though. And they planned to install it today. But they failed to finish all software updates before 17.30 so they will do it tomorrow.
Same with other non software issues: tick/rattle front left wheel, washer nozzle everywhere but on the windscreen.

ReintjeWA · Feb 13, 2025

Mine is getting the bracket on the 27th this month, the dealer never argued or anything. I called them and said I have the under tray bulge, they said bring it in for us to confirm please, and then they ordered the part to come from the East coast that same day.

I think the only way it would’ve been better is if they had some local stock, it can’t take up too much space on a shelf this thing. But perhaps MG will pay upon ordering the part, so they don’t want to buy their own stock, who knows?

NLMGSAN · Feb 13, 2025

They did install it on mine today as well.

DixieTGS · Feb 13, 2025

I guess the dealers are quite happy to do this work if possible - I suspect they're never going to lose out if they're paid for 12 minutes of time to undo 3 bolts and do up 3 others.

LenEV2016 · Feb 13, 2025

DixieTGS said:
I guess the dealers are quite happy to do this work if possible - I suspect they're never going to lose out if they're paid for 12 minutes of time to undo 3 bolts and do up 3 others.

Plus they aren't fabricating the part it comes from old mechano sets

NLMGSAN · Feb 13, 2025

LenEV2016 said:
Plus they aren't fabricating the part it comes from old mechano sets

As long as it does the trick.

LenEV2016 · Feb 13, 2025

NLMGSAN said:
As long as it does the trick.

Embarrassing though, just design it correctly in the first place.
Don't persist in fitting them when it's obvious the holes don't line up.
And don't lie when questioned by customer and state it's a characteristic.

MG4 Undertray dip/bulge

Standard Member

Prominent Member

Established Member

Established Member

Standard Member

Established Member

Standard Member

Distinguished Member

Standard Member

Established Member

Prominent Member

Standard Member

Distinguished Member

Prominent Member

Established Member

Prominent Member

Established Member

Established Member

Prominent Member

Established Member

Similar threads

Yes

I'm in the middle

No

Latest MG EVs video