MG4 Undertray dip/bulge

[Deleted member 10041]

Just had a squint underneath mine. Phase 2 SE LR.

View attachment 19463

Can't believe they are still coming that bad, how hard would it be to fix it.
There is going to be so much crap from winter roads going in there

 

[OriginalBigAl]

My phase 2 SE LR 23 has slight bulges , not as bad as the above photos, and a new trophy 23 I looked at was the same. Both dealers I pointed this out to could not care less. The main issues are that this is a well known documented issue, and that if the quality is poor on bits you can see, what about the quality on bits you can,t and of course individual dealers responses. I,ll be going down the self fix road but agree with all comments that it should be a dealer fix. Then again it should not be there in the first place.

 

[Deleted member 10041]

I get why people are going to fix them themselves, but you really shouldn't have too! But the fact they are still coming a year in, reflects really poorly on MGs attitude to quality control

 

[Rolfe]

It's deeply depressing.

I'm not sure whether my dealer made a lot of difference. I'm unsure whether a fix using the existing tray is practical - if it is, I'd be prepared to pay my local garage to do it. But I don't intend to pay for a replacement tray! I'm also concerned that some members have said that replacement trays are arriving already warped and having to be re-ordered. I'm waiting eagerly to see how @PristDean gets on, because his determination is getting results.

 

[SimonS]

I've emailed the dealer and they will book it in to be dealt with. No fuss. No questions.

I on the other hand am wondering, given this is so well known, why this wasn't checked and attended to before delivery. It seems that these days a PDI only involves a hose and a sponge.

 

[Rolfe]

You want my actual opinion? They know most drivers don't peer under their cars to notice something like that, so they're just letting them go and hoping only a fraction will be thrown back at them.

And then they seem to be stalling that fraction too, or at least some of them.

 

[OriginalBigAl]

I do not know how many MG4s they are expecting to sell. I,ll use an arbitrary figure of 100 000, SAIC will go to 3rd party plastics manufacturer and give them the design brief. Tooling will be made for the presses, and there could be a row of presses as opposed to just one, there could be slight differences in tooling quality , heating, pressure distribution of each press. This results in differences in each undertray made. SAIC may complain about the quality but things have gone some way down the line and re-tooling costs and delivery times are prohibitive and there could be a stock pile to get rid off. Hence some have no problems and some do and I,ll refer you to Rolfe,s previous reply.

 

[Eber]

I,ll be going down the self fix road but agree with all comments that it should be a dealer fix. Then again it should not be there in the first place.

Of course the dealer should fix it - as has already been done with some cars in this forum. Under no circumstances would I fiddle with a part of the car under warranty. What if some part of the plastic breaks off? They wont't touch it then and you are responsible. Make the dealer do it. It's their job.

 

[Nobbyplopps]

Do you guys think the undertray dip/bulge is due to a “bad batch” or is this issue common with all MG4s? I get mine delivered in September and this will be the first thing I will be checking. Has anybody received their MG4 without this issue?

 

[Rolfe]

@alix said his car was OK. Identical car to mine, bought from the same dealer two weeks before mine.

 

[tsedge]

Do you guys think the undertray dip/bulge is due to a “bad batch” or is this issue common with all MG4s? I get mine delivered in September and this will be the first thing I will be checking. Has anybody received their MG4 without this issue?

The vast majority of the public won't be looking under their cars, so we don't know the true extent. There have certainly been some owners without this issue.

It doesn't appear to have been addressed on newer cars and MG's line seems to be that it is fine / as intended / not a real problem, though more and more people are reporting their dealers willing to try to fix it.

I haven't yet seen many reports of it causing a problem, beyond the expectation that it will marginally affect range / get clogged up.

Back with the earliest cars, someone had a huge dip/bulge and reported that the undertray was ripped off when they drove through a flood - but it is hard to know if that was a one-off, due to the flood depth or a general risk.

I remember with my old MX5 the exhaust heatshield fell off (big metal sheet under the car) and the Mazda dealer said it was fine without it, they often removed it and they were right.

So it also depends whether the undertray is doing a useful job or not. These things can make little or no difference.

 

[Nobbyplopps]

The vast majority of the public won't be looking under their cars, so we don't know the true extent. There have certainly been some owners without this issue.

It doesn't appear to have been addressed on newer cars and MG's line seems to be that it is fine / as intended / not a real problem, though more and more people are reporting their dealers willing to try to fix it.

I haven't yet seen many reports of it causing a problem, beyond the expectation that it will marginally affect range / get clogged up.

Back with the earliest cars, someone had a huge dip/bulge and reported that the undertray was ripped off when they drove through a flood - but it is hard to know if that was a one-off, due to the flood depth or a general risk.

I remember with my old MX5 the exhaust heatshield fell off (big metal sheet under the car) and the Mazda dealer said it was fine without it, they often removed it and they were right.

So it also depends whether the undertray is doing a useful job or not. These things can make little or no difference.

We shall see in September when it arrives

 

[Eber]

Do you guys think the undertray dip/bulge is due to a “bad batch” or is this issue common with all MG4s? I get mine delivered in September and this will be the first thing I will be checking. Has anybody received their MG4 without this issue?

Some have it, some don't. Since they are still delivered with this fault it's just sh*t quality control.

 

[tsedge]

There was even a chap in Spain whose car was delivered without an undertray at all, which I suppose is one solution!

 

[Kithmo]

Are the ones who don't have the bulge missing out ?

 

[Emgie 4]

Are the ones who don't have the bulge missing out ?

Is that a bulge in your undertray? Or are u just happy to see me ?
Sorry, I couldn't resist ?

 

[Yandards]

The vast majority of the public won't be looking under their cars, so we don't know the true extent. There have certainly been some owners without this issue.

It doesn't appear to have been addressed on newer cars and MG's line seems to be that it is fine / as intended / not a real problem, though more and more people are reporting their dealers willing to try to fix it.

I haven't yet seen many reports of it causing a problem, beyond the expectation that it will marginally affect range / get clogged up.

Back with the earliest cars, someone had a huge dip/bulge and reported that the undertray was ripped off when they drove through a flood - but it is hard to know if that was a one-off, due to the flood depth or a general risk.

I remember with my old MX5 the exhaust heatshield fell off (big metal sheet under the car) and the Mazda dealer said it was fine without it, they often removed it and they were right.

So it also depends whether the undertray is doing a useful job or not. These things can make little or no difference.

It's got to making some difference or why would they spend the money on the thing to both build and fit?

Don't think it's sole job is to keep the road crud away from the power train as you could achieve the same with less plastic and arguably less cost.

To me it's a dual function part, primarily for aerodynamic reasons to help with efficiency, secondly as a crud guard.

I've noticed some interesting aero having done the 500 odd motorway miles over a couple of days - front tyre gel is still in a good state, the rears have completely gone.

 

[siteguru]

I've noticed some interesting aero having done the 500 odd motorway miles over a couple of days - front tyre gel is still in a good state, the rears have completely gone.

Sorry but I've no idea what you're talking about here. ?

 

[Yandards]

Sorry but I've no idea what you're talking about here. ?

The tyre gel is just sidewall blackening stuff.

The front wheel sidewalls are showing they have been protected from road gunk - the rear sidewalls have not. This indicates turbulent airflow around the rear wheels.

 

[PristDean]

It's got to making some difference or why would they spend the money on the thing to both build and fit?

Don't think it's sole job is to keep the road crud away from the power train as you could achieve the same with less plastic and arguably less cost.

To me it's a dual function part, primarily for aerodynamic reasons to help with efficiency, secondly as a crud guard.

I've noticed some interesting aero having done the 500 odd motorway miles over a couple of days - front tyre gel is still in a good state, the rears have completely gone.

I agree about the under tray. If on a Trophy gaps will just create more down force coupled with the rear spoilers, this will create more drag and reduce efficiency, especially at motorway speeds.

Coupled with protecting the rear motor and BMS system. As you say, they put it there for a reason