MG4 Undertray dip/bulge

[Nobbyplopps]

Hi all here just returned from my dealer who has just replaced the undertray on my wife’s MG4 SE SR and what a disappointment when the replacement was in place the technician ask me to come into the workshop to have a look while the car was still on the ramp the old tray was on the floor and the new one now on the car with exactly the same bulge as the old one nothing more they can done the technicians said, and he then added they are all the same on the MG4s with varying amounts of the bulging from on car next he agreed it’s not good but said it is of no detriment to the vehicle or its performance.
Before and after pictures below. So it is what it is I suppose.
Les.

Old tray beforeView attachment 24840View attachment 24841

New tray fitted today
View attachment 24842View attachment 24843

Have not just given it a clean?

 

[OriginalBigAl]

Hi all here just returned from my dealer who has just replaced the undertray on my wife’s MG4 SE SR and what a disappointment when the replacement was in place the technician ask me to come into the workshop to have a look while the car was still on the ramp the old tray was on the floor and the new one now on the car with exactly the same bulge as the old one nothing more they can done the technicians said, and he then added they are all the same on the MG4s with varying amounts of the bulging from on car next he agreed it’s not good but said it is of no detriment to the vehicle or its performance.
Before and after pictures below. So it is what it is I suppose.
Les.

Old tray beforeView attachment 24840View attachment 24841

New tray fitted today
View attachment 24842View attachment 24843

Have they let you take, or can you get the old tray? You could stiffen the front edge whilst it's off the car, then replace the second faulty unit. Then do a similar fix to that, then like pass the parcel, pass it on to another member who can do the same, eventually we will all have a straight tray without bothering MG.

 

[Les burrows]

You have a point Siteguru but as anyone seen this down under fix i don’t recall seeing any pictures.
Les

Have not just given it a clean?

No no it’s a new tray I can assure you of that.
Les

 

[NLMGSAN]

No no it’s a new tray I can assure you of that.
Les

So MG is only in for the penny. Not for the pound...

 

[Les burrows]

So MG is only in for the penny. Not for the pound...

There are times I wonder if they MG are in after sales at all. Very disappointing result.
Les

 

[AndyL61]

They keep getting away with it . Incredible!

 

[NLMGSAN]

They keep getting away with it . Incredible!

I'm sure there is a serious airflow underneath the car. So basically, you are driving with the MG's mouth open. And that air gets trapped in the car?

 

[Les burrows]

I'm sure there is a serious airflow underneath the car. So basically, you are driving with the MG's mouth open. And that air gets trapped in the car?

Hi no not really what ever goes in that dip/gap on the front edge will come out again at the back of the tray the only concern I have is how much muck is getting in around the motor etc.
Les

 

[siteguru]

You have a point Siteguru but as anyone seen this down under fix i don’t recall seeing any pictures.
Les

I can't remember which thread it is in, but this was one of the photos with the fix fitted:

(This was the photo I emailed to my dealer, hence why I was able to find it).

 

[Les burrows]

Thanks for that Siteguru I think from what I could see yesterday while the car was up on a-ramp the issue is the transmission casing the tray looks very very close to it just off centre of the car.
Les

 

[NLMGSAN]

Hi no not really what ever goes in that dip/gap on the front edge will come out again at the back of the tray the only concern I have is how much muck is getting in around the motor etc.
Les

Then where and how does it flow out?

When they corrected the steering wheel position I was invited to have a look the way MG had been assembled the car. I could not see any air openings at the back to let the air out. My MG has a vary minor bulge btw.

 

[Les burrows]

Then where and how does it flow out?

When they corrected the steering wheel position I was invited to have a look the way MG had been assembled the car. I could not see any air openings at the back to let the air out. My MG has a vary minor bulge btw.

The tray is underneath the car and Air or anything else should not enter the car via that area so it will just flow out of the back or out the rear wheel aches.
Les

 

[NLMGSAN]

Next time it is up I will ask them to take it off. If there is no free frictionless airflow it will definitely increasing resistance.

 

[mg4mc]

Next time it is up I will ask them to take it off. If there is no free frictionless airflow it will definitely increasing resistance.

Probably less than no tray at all though. Then there are all sorts of voids exposed to the airflow and it will become very turbulent.

 

[GrayCat]

So, got under my car with an industrial hot air fan / blower. Tried to heat up and re-form the edge of the plastic shield.

That was rather hard. The plastic is some complex "Glass-filled polypropylene (???)" or similar composite. It doesn't get "soft" when hot, instead it turns into "grease with fiber". So, it is very "elastic". You straighten up one part of the edge — while the other gets "bulged" again! It took me several passes to fix everything up, all the time heads-up and "pushing the sky".

I think, if someone wanted to thermo-form this part, it would be much easier to take it off (a dozen of bolts and screws), and proceed in comfort place.

Anyway, after bending the edge up (to the bottom of the battery), the "crack" was almost gone. And, to the glory of Savage and Heinemann , the roll of "Duct Tape" finished the deal!

 

[DixieTGS]

Thanks for the write up and photos. I was going to to do much the same when I next got access to some ramps.

Following your comments I think I'll stick to my plan and remove the tray, then do it off of the car. I was a bit worried about damaging other bits with the heat anyway.

 

[DaevM]

Aaaand here we are. Yet another example. Asked them to inspect prior to delivery. They were bemused by my request " never had any examples of this in the 20 or so I've sold" ( it's Cornwall). Well, you have now buddy.
591 miles in the clock and I've got an easily noticeable bulge. Well, the car has.
Trouble is I'm 250 miles of M-way driving away. I'm sure it'll be fine.
Potential 800 mile round trip coming up this weekend after my 250+ mile return trip. One phone call coming up.
Thanks forum for being on the nail and raising awareness.

As an aside, this was definitely a perfect fit, no droopy bulge when I collected it .

Booked in next Wednesday...

 

[Archev]

So, got under my car with an industrial hot air fan / blower. Tried to heat up and re-form the edge of the plastic shield.

That was rather hard. The plastic is some complex "Glass-filled polypropylene (???)" or similar composite. It doesn't get "soft" when hot, instead it turns into "grease with fiber". So, it is very "elastic". You straighten up one part of the edge — while the other gets "bulged" again! It took me several passes to fix everything up, all the time heads-up and "pushing the sky".

I think, if someone wanted to thermo-form this part, it would be much easier to take it off (a dozen of bolts and screws), and proceed in comfort place.

Anyway, after bending the edge up (to the bottom of the battery), the "crack" was almost gone. And, to the glory of Savage and Heinemann , the roll of "Duct Tape" finished the deal!

Well duct tape and silicone hold the rest of the world together so that sounds perfect

 

[DaevM]

Usual response from dealer
1. It's not a thing.
Me:- can i see the specifications that show it's within design tolerances.
2. We can't locate those but will keep it on record so that should it become an issue we have a record....
Me:- There's over 40 pages worth of posts about it on MGEVs forum. It's a known issue. Mentioned MGAUS appear to have issued a solution.Please contact MGUK and find out how they are progressing it.
3. Righty-ho.

We will see but I'm guessing I shouldn't hold my breath.

 

[fnegroni]

Before I read 40 pages of posts, does the fix/modification (official or not) show any improvements in terms of aerodynamics whether it’s noise reduction or energy consumption?