MG4 Undertray dip/bulge

[Lovemyev]

Leaf?

Agreed !.
A problem of having the bulge there, is that it acts like a scoop. !.
As the car is travelling forward, because the bulge is in a “Into Wind” condition, it will catch any dried leaves on route !.
I am curious …,,,, what is that thing in the shot, it looks like a black coloured pipe with two retaining clips securing it ?.
It is more likely to be an electrical cable ??.
It looks like it is preventing the under tray from fully closing and therefore being flush with the underbody ?.
It’s hard to tell really.
I would love a look at one, up on a lift !.

 

[siteguru]

I think that's just a parallax error - the viewing angle makes it look lower than it actually is.

 

[Ian Key]

I would love a look at one, up on a lift !.

Me too. I'm sure an additional support could be "bodged" to support the undertray.

 

[snurt]

Silver looks great though

 

[Hallix73]

Me too. I'm sure an additional support could be "bodged" to support the undertray.

I am sure that would be relatively simple. Small box section aluminium adhered with two part araldite to the tray. Maybe increase hole size and put a penny washer to fix up again to allow for the rigid center part. If MG say it is not a required fix I think I will do this. I have friend who has a car lifter so should be easy to do.

 

[Ian Key]

I am sure that would be relatively simple. Small box section aluminium adhered with two part araldite to the tray. Maybe increase hole size and put a penny washer to fix up again to allow for the rigid center part. If MG say it is not a required fix I think I will do this. I have friend who has a car lifter so should be easy to do.

The simplest option could be to elongate the holes in the plastic tray to allow it to flatten out. Might have to clip the sides of a penny washer to allow it to remain inside the indentation.

 

[siteguru]

Do the bolts have spring or crinkle washers underneath the heads? I can see that being a worthwhile addition if not, else they're more prone to vibrate loose.

 

[Ian Key]

Do the bolts have spring or crinkle washers underneath the heads? I can see that being a worthwhile addition if not, else they're more prone to vibrate loose.

Bit of thread-lock would resolve that.

 

[memo]

So, we just had a test drive in a Luxury MG4 in Valencia and Alicante, Spain. When asked about the problem with the oil leak and this threads rear underbody tray bulge both told us that they have not heard about it, nor seen it at all, but Valencia did also say that they had very few cars as of yet.

Well I looked at the 2 cars in Valencia their demonstrator (luxury, uk's trophy) and their standard (UK's SE SR) and neither showed any sign of the problems.

The day before our test drive with the MG4 in Alicante a couple of weeks ago the salesman text and said the car is in the workshop for "tuning" so I only got to test it on Saturday, 3 days ago. So after the test drive I ask was it in the workshop for the oil leak, "No" he says "just for software updates etc".

When I look under the car, guess what! the rear underbody tray is completly missing. When asked why he replied (genuinely, I believe) "Oh! is there supposed to be one, we can look at the other one in the showroom" (my translation).
Looked under the other one and Yep! has the underbody tray bulge, in fact had 2 bulges either side of center where i could get most of my hand in. Did not see any signs of an oil leak though.

So, although only 4 cars I would say it looks to me that the european cars have the same faults.

 

[Tig170]

When I look under the car, guess what! the rear underbody tray is completly missing. When asked why he replied (genuinely, I believe) "Oh! is there supposed to be one, we can look at the other one in the showroom" (my translation).

... thanks for enlightening us!! - you can also see what MG's solution is going to be! - just remove it pre-delivery / 1st service - as I'm not sure what purpose it serves in anycase?

 

[memo]

... thanks for enlightening us!! - you can also see what MG's solution is going to be! - just remove it pre-delivery / 1st service - as I'm not sure what purpose it serves in anycase?

At low speed probably not a lot, if any difference to aero, range, but i think at high speeds it would keep the air flowing straight and not cause eddies, as I think without it the air would be sucked up into the motor space and cause drag. Plus of course it would I'm sure stop a lot of the dirt etc from getting all over the motor etc.

 

[siteguru]

And also prevent any road debris getting flicked up into the motor.

 

[Deleted member 10041]

... thanks for enlightening us!! - you can also see what MG's solution is going to be! - just remove it pre-delivery / 1st service - as I'm not sure what purpose it serves in anycase?

Miles on the podcast last night said it was to stop dirt and muck going up into the motor, the fact the bulge/gap is forward facing kind of make the reason redundant as at this time of year loads of road muck could end up in there

 

[Lovemyev]

The simplest option could be to elongate the holes in the plastic tray to allow it to flatten out. Might have to clip the sides of a penny washer to allow it to remain inside the indentation.

I agree.
My OCD tell's me that I would just like to drop the tray and then first measure and record the hole pitches measurements in the body shell.
Secondly, apply some hot air to the under tray, just to see if it returns it's once natural factory moulded shape.
If it does, now compare the measurements of the hole pitches in both items.
Maybe even lay the plastic under tray on a flat surface on the floor, with long sheet of plain paper ( wall paper would do ) under the tray and then transfer the hole pitches onto the paper.
Now compare these figures on the tracing, to the hole pitches on the body shell.
This could quickly show which hole pitches are causing the distortion / bulge in the tray when trying to install ALL of the fastens.
This may indicate if slotting the holes would then allow achieving all of the fastens, with out distorting the tray.
I am think along the same lines of "slotting" the holes in the tray, to then achieve the pick up points in the shell correctly.
My guess would be, that some ( if not all of the holes ) in the rear of tray, would benefit from slotting.

 

[bear1]

Just popped over to my dealer to pay for my car - collect on Saturday. Had a good look at the cars external, and it does appear to have a slight bulge. Certainly won't stop me going ahead with the purchase, but will get the dealer to record it and keep me informed.
Otherwise, all looked good. Looks awesome!

 

[Kithmo]

Split it and plastic weld it.

 

[jamesc83]

Just popped over to my dealer to pay for my car - collect on Saturday. Had a good look at the cars external, and it does appear to have a slight bulge. Certainly won't stop me going ahead with the purchase, but will get the dealer to record it and keep me informed.
Otherwise, all looked good. Looks awesome!

Enjoy your new car! The bulge isn’t stopping me enjoying it.

Probably worth emailing mg customer service when you have a minute. As with everything the more people report it/complain about potential efficiency loss etc the more likely they will do something.

Great car though, have fun

 

[TallPaul]

I wonder if some thick insulation type foam can be cut to plug the hole as a temporary fix. I would be worried of water ingress during winter time and this might stop the noise issues people are reporting.

 

[jamesc83]

I wonder if some thick insulation type foam can be cut to plug the hole as a temporary fix. I would be worried of water ingress during winter time and this might stop the noise issues people are reporting.

Maybe, water ingress doesn’t concern me too much, it has drain holes and the motor on the ZS was wide open to the elements

 

[jamesc83]

So I thought I’d chase this as I hadn’t been in touch with MG in a couple of weeks. This is what I got back. This time from someone called Ella not Gary.

Thank you for your email and I hope that you are well.

There has been no formal communication released to the dealership network regarding the MG4 undertray to date, please accept my apologies for any confusion from previous correspondence.

There will be a communication released to the dealership network in the future regarding this but we cannot put a time scale on when this will be published.
This is because MG will be testing a modified undertray from SAIC.

At this stage, there has been no guarantee from seniors at MG Motor UK that undertrays will be replaced with a modified one as we are still at premature stages.

I would recommend keeping in touch with your dealership who can provide you with a finalised update once a communication has been published to them.

Thank you again for your email and I wish you a pleasant weekend.

So mixed messages but we’ll see.