MG4 Reduction Gearbox Oil Leak

[wiz043]

Yes, Mulan has the same leaking issue.
But seems not that many.

They MG4 (Mulan) came out in China in June last year and some had leaks as you suggest. They did not get to the UK until October yet some of those still had leaks up until the ones supposedly built in December and later. MG in China had 4 months to sort the leak out but apparently did nothing about it.
We still do not know whether the 'solution' was to drop the oil level in the reduction gearbox 200ml or so in the later models so as to avoid it being flung out the breather 'spout', even allowing for the fitting of modified breathers.
Until that is clarified the issue even with latest built ones is still uncertain.

 

[spence7788]

Apologies for the delayed reply to some Q's (newborn limits spare time & sleep atm ).

It's more of a "baby fireblade" Cbr650r but I've only been past my bike test a year so it's still plenty fast enough for me whilst I'm getting some miles in, think it's still 0-60 in 3. odd seconds and usable on the road, managed to get to croft last weekend, was great to be out again & sunny!

No worries at all Les, sorry the pics I took aren't fantastic but I've attached a couple of pics here sort of showing where the fill hole is located and one I managed to get if it, once your under it's pretty obvious as it's the only one there, there's literally just the fill on top & drain on the bottom of the diff casing.

Re the undertray, I have got a slight bulge there which isn't fantastic but it's not terrible tbh, I just put it back on as is, I could have slotted a couple of the undertray fixings larger to probably fix it & give it more space but on mine, it's really not massive and not acting as a air scoop or anything.

That is the exact pump Andy has posted, I've always used the suction gun type but this worked better than I could have imagined. I got it cheaper with my Halfords card but the similar Sealey ones etc. Are about £15 on eBay I noticed.

Cheers Stephen

 

[spence7788]

Pics

 

[Les burrows]

Great thank you very much Stephen I very much appreciate your response as I’m sure others here will also great job now get some sleep as the newborn will be needing you soon I remember it well you go through that in life and then some 20-30 years later you might have to do it all over again with grand kids but some how 2nd time it a piece of cake thanks again
Les.

 

[maverickz]

They MG4 (Mulan) came out in China in June last year and some had leaks as you suggest. They did not get to the UK until October yet some of those still had leaks up until the ones supposedly built in December and later. MG in China had 4 months to sort the leak out but apparently did nothing about it.
We still do not know whether the 'solution' was to drop the oil level in the reduction gearbox 200ml or so in the later models so as to avoid it being flung out the breather 'spout', even allowing for the fitting of modified breathers.
Until that is clarified the issue even with latest built ones is still uncertain.

Search my previous post, I have listed the feedback from a dealer in China.

 

[wiz043]

Search my previous post, I have listed the feedback from a dealer in China.

Yes, I saw that you referred to the leak apparently only in a few Chinese Mulans.
If you are referring to the drop to 700ml in another of your posts it confirms what now may be the case as I suggested but if the 'box was designed to hold 900ml what does that indicate...trial and error?
Some here are still getting leaks with the oil level reduced, some not and some even with the 'modified' breather, there does not appear to be a pattern leading to a solution.
If the latest models Nov/Dec. build supposedly with the new breather are not leaking it would be interesting to know if the oil has been reduced to 700ml or less.
If so, that would be a concern in my view.

 

[Deleted member 10041]

Yes, I saw that you referred to the leak apparently only in a few Chinese Mulans.
If you are referring to the drop to 700ml in another of your posts it confirms what now may be the case as I suggested but if the 'box was designed to hold 900ml what does that indicate...trial and error?
Some here are still getting leaks with the oil level reduced, some not and some even with the 'modified' breather, there does not appear to be a pattern leading to a solution.
If the latest models Nov/Dec. build supposedly with the new breather are not leaking it would be interesting to know if the oil has been reduced to 700ml or less.
If so, that would be a concern in my view.

We are assuming that it's a bit of both that's stopping the leak, new breather and reduced oil, the only 2 people to drain their box have got about 600-700mls. I'm sure Macadoodle said it pretty much had to stop leaking about that level.

 

[wiz043]

We are assuming that it's a bit of both that's stopping the leak, new breather and reduced oil, the only 2 people to drain their box have got about 600-700mls. I'm sure Macadoodle said it pretty much had to stop leaking about that level.

It appears so...the only thing we do not know for sure is the effect on the reduction gears if the oil is reduced by 200ml to 300ml when the 'box was designed for 900ml.
Perhaps MG do not know either and are just rolling the dice hoping that it doesn't lead to a much bigger expensive issue for them.

 

[tsedge]

It appears so...the only thing we do not know for sure is the effect on the reduction gears if the oil is reduced by 200ml to 300ml when the 'box was designed for 900ml.
Perhaps MG do not know either and are just rolling the dice hoping that it doesn't lead to a much bigger expensive issue for them.

They apparently consulted with the gearbox manufacturer before doing this so it is highly unlikely to be a roll of the dice, especially as it would have very expensive consequences for MG if they got it wrong.

Such low stress applications usually have a wide tolerance on the oil level. Even high stress applications like an ICE engine permit a litre between min and max.

Once again, we are not seeing reports of gearbox failures, there's no evidence of a problem with the new level.

 

[Macadoodle]

From Maverickz pics it would appear that the oil level should sit half way up the intermediate shaft that transfers drive from the motor output to the diff.
I think the level would have to get seriously low, almost empty, for these four gears to have no lubricant coating them.
Splash and throw to the bearings might be a different matter though, it obviously reduces as the oil level drops as that's why the thing leaks less, but how much splash is just enough to keep them lubed

 

[wiz043]

Splash and throw to the bearings might be a different matter though, it obviously reduces as the oil level drops as that's why the thing leaks less, but how much splash is just enough to keep them lubed

Exactly, and regardless of MG's apparent 'consultation' with the gearbox manufacturer about the possible issues regarding a lower oil level why did they design it to hold 900ml in the first place I wonder?

It still appears to me that they let some oil out as a bandaid fix as many were still leaking with the new modified breather fitted so they probably just got sick of dealing with the issue.

They are well aware of what causes the leak but it appears they just do not want to outlay enough cash/resources to solve the problem properly, although your solution @Macadoodle or something similar would work and probably cost less than the modified breathers which may or may not work.

There is no evidence of a problem with the new lower oil level....YET, but it's early days.
MG and dealers are not renown for giving information and for customer service based on countless comments here and I would not be surprised if they have now adopted a 'suck it and see' attitude re lowering the oil level in faulty cars as I suggested earlier.

My view only...others may differ.

 

[Cocijo]

Less oil equates to more work for the reduced quantity to have to do.
This might mean that the oil needs to be changed more often or it might mean reduced effectiveness under certain conditions. The reduction in oil quantity is over 20%.
It might also mean that it performs ok with no change in efficiency. We don’t know.

But, as has been said, my concern would be that if the designers of the gearbox have calculated the required amount of oil needed for optimum performance, to then reduce this to stop leaks seems at best a short term reaction.
I am concerned about how dark the oil seems when drained, which usually means it’s done its job but needs to be changed. If there is no official scheduled oil change the oil will only deteriorate more.
As some have done, an initial oil change after the running in period seems very sensible at the very least. Of course if you’re not keeping the car you are probably not that concerned. Others will quite rightly say it‘s for MG to sort out - which is true. The worry for those keeping their cars longer is how MG would deal with any future related issues, given how bad they are when dealing with claims.
It could all be something about nothing and the gearboxes run for hundreds of thousands of miles with no issues - but it’s about confidence after all and that is not something that MG are good at instilling.

 

[Les burrows]

Hi again guys now this morning I have been doing a bit of back tracking as I remembered an issue with gear oil for the MG5 which is the very same oil and if you do a search and read that thread a member called m4rmitr who apparently as good knowledge about oils has said at#27 in that thread the dark colour of the oil coming out of the gearbox is down to oxidisation which appears to be the cause.
Sorry but I don’t know how to post a link to the thread but I have put the title of it below it’s 3 pages of interesting information yes it the MG5 but the same oil and likely s as me gearbox. I’m not sure if the person I name above is still on the forum or not or if he’s been involved with this thread about the 4
Les

Reduction Box Oil​

• Thread starterLucky5
• Start dateAug 19, 2021

 

[Cocijo]

Is oxidisation a bad thing or just normal?

 

[tsedge]

Exactly, and regardless of MG's apparent 'consultation' with the gearbox manufacturer about the possible issues regarding a lower oil level why did they design it to hold 900ml in the first place I wonder?

It still appears to me that they let some oil out as a bandaid fix as many were still leaking with the new modified breather fitted so they probably just got sick of dealing with the issue.

They are well aware of what causes the leak but it appears they just do not want to outlay enough cash/resources to solve the problem properly, although your solution @Macadoodle or something similar would work and probably cost less than the modified breathers which may or may not work.

There is no evidence of a problem with the new lower oil level....YET, but it's early days.
MG and dealers are not renown for giving information and for customer service based on countless comments here and I would not be surprised if they have now adopted a 'suck it and see' attitude re lowering the oil level in faulty cars as I suggested earlier.

My view only...others may differ.

It is all possible, but it is just speculation in the dark at the moment.

Less oil equates to more work for the reduced quantity to have to do.
This might mean that the oil needs to be changed more often or it might mean reduced effectiveness under certain conditions. The reduction in oil quantity is over 20%.
It might also mean that it performs ok with no change in efficiency. We don’t know.

But, as has been said, my concern would be that if the designers of the gearbox have calculated the required amount of oil needed for optimum performance, to then reduce this to stop leaks seems at best a short term reaction.
I am concerned about how dark the oil seems when drained, which usually means it’s done its job but needs to be changed. If there is no official scheduled oil change the oil will only deteriorate more.
As some have done, an initial oil change after the running in period seems very sensible at the very least. Of course if you’re not keeping the car you are probably not that concerned. Others will quite rightly say it‘s for MG to sort out - which is true. The worry for those keeping their cars longer is how MG would deal with any future related issues, given how bad they are when dealing with claims.
It could all be something about nothing and the gearboxes run for hundreds of thousands of miles with no issues - but it’s about confidence after all and that is not something that MG are good at instilling.

I expect as we get some higher mileage examples in for their first service, MG will do some inspections and this may lead to a revised schedule for changing the gearbox oil.

It is quite normal for manufacturers to update their recommendations once there's enough real world usage. This happens all the time with ICE vehicles - the cambelt interval on some VAG petrol engines was revised not that long ago but it doesn't mean everyone's belt is about to go bang if they are not instantly changed. It didn't cause a fuss.

In general I am not worried about it the MG4 gearbox, the warranty covers it, reduction gearboxes are not a new technology and we are not seeing failures.

There's an endless series of bad things that 'might' happen with any vehicle. I suppose it seems to me that there's a bit of a hypersensitivity around these things with EVs which doesn't seem warranted given that they are much simpler mechanically and should be more reliable.

 

[Macadoodle]

In general I am not worried about it the MG4 gearbox, the warranty covers it.

Unless it spits gear teeth through the casing or seizes solid I really wouldn't hold out much hope for that.
I would bet my house that someone complaining about bearing whine in a couple of years time will get absolutely nowhere with MG.
The aircon compressor chirping like a budgie is normal to them, doesn't bode well.

 

[wiz043]

Unless it spits gear teeth through the casing or seizes solid I really wouldn't hold out much hope for that.
I would bet my house that someone complaining about bearing whine in a couple of years time will get absolutely nowhere with MG.
The aircon compressor chirping like a budgie is normal to them, doesn't bode well.

This situation is a bit like MG saying " oh, some owners have been complaining about the MG4 riding too hard so rather than spend money on the suspension let's drop the tyre pressures from the recommended 37 psi to around 22 psi, The car will ride much softer but probably won't go around corners as well and the tyres will wear out much quicker but hey, not our problem".
Tongue in cheek...

 

[paulgailey]

The ace news to me of this interview is that MG Spain are going to offer a compliant roof rack, box and tow attachment for the MG4. I test drove one here this week in Spain and it's apparent unavailability was for me the only negative, so this is great news. The govt plan incentive here currently offers €7000 discount when you trade in and crush your old ICE. MG also front up that discount for 12 months whilst you chase it from the regional government who are notoriously slow on these matters. I'm very tempted.

Unfortunately its not just this forum or indeed just UK, its reported in all countries and here in Spain. Here is a 38 min youtube video just this week with an interview, with José Antonio Gálvez responsable for the product and press of MG Spain and Portugal, about this oil leak and the many other problems which are being discussed in this forum. Dont want to listen to 38 mins of Spanish Just go to 3:53 and hear what the guy from MG says about the cause of the oil leak. Oh! dear! any body heard this before.

Sorry only in Spanish but you can turn on CC in youtube and select auto translate to English, not perfect but you can understand quite well.

 

[memo]

The ace news to me of this interview is that MG Spain are going to offer a compliant roof rack, box and tow attachment for the MG4. I test drove one here this week in Spain and it's apparent unavailability was for me the only negative, so this is great news. The govt plan incentive here currently offers €7000 discount when you trade in and crush your old ICE. MG also front up that discount for 12 months whilst you chase it from the regional government who are notoriously slow on these matters. I'm very tempted.

If you live in a village of less than 5000 people like we do then it's another 500 euros on top of that.
Remember though the crush the ice subsidy is only 2500 euros so if like us your car is worth more still better to sell it.
Haha yep the government are certainly slow in paying you, but also remember this is paid back in and when you declare your IRPF so 1 to 2 years later.
Also mg only discount that for a year if you choose there finance terms, not when you pay cash.

 

[paulgailey]

With ALL incentives (except that additional small village -€500) the Standard MG4 = €20480

My 20 year old Saxo diesel wouldn't get €1k on 2nd hand market so probably worth reviving it for such a hefty discount, no?