MG4 Reduction Gearbox Oil Leak

[tsedge]

There is still something that doesn't add up from an engineering perspective.
If all UK cars come out of the factory with the same oil level and breather design there is nothing arbitrary about whether a problem should manifest. There must be a variable that's occurring at their end and the only thing that comes to mind for me is how much oil they put in the gearbox at its first fill.

Yes. Perhaps the early cars were overfilled and the poll is dominated by these?

 

[Les burrows]

Is there a link between this and the bulge in the undertray?

I can’t say if it does or not ours has the bulge but no oil leaks as yet in some of the pictures I have seen the stain from the oil leak looks like it coming from around where the trays is bulging and has blown backwards It could well be the bulge because it would be the lowest point on the tray might be like a little well for any leaking oil to run into perhaps but I don’t know.

The bulging in the tray on our car is quite big and I can get all my fingers in it no problem could I would think get my hand in there but there is not oil present at the moment pictures below the green Circle you can see is from my torch.
Les

 

[Gem10]

I presume they didn't detect this in the Asian cars because the motor/gearbox are different.

I have not seen this mentioned on any of the Chinese reviews or presentations. The hardware is the same only the software looks different in the Flagship (Extended Range)model.

 

[Alb]

Yes. Perhaps the early cars were overfilled and the poll is dominated by these?

There still seems to be a fundamental design issue with the location of the breather but I could visualise a situation where a combination of the original breather plus a normal or greater than normal oil level resulted in leakage whereas a combination of the original breather plus a less than normal oil level resulted in no leakage.

 

[tsedge]

I have not seen this mentioned on any of the Chinese reviews or presentations. The hardware is the same only the software looks different in the Flagship (Extended Range)model.

Do we know that the motor/gearbox is the same? It often isn't with Asian models because they are built to a different price point and spec. Maybe it is with the MG4. It's been speculated before that the gearbox manufacturer had a different design/spec for the UK/EU markets.

 

[BugEyed]

It doesn't sound like the breather is faulty in terms of engineering, it is the design that is the problem, hence why they are adding a long pipe.

I'm being dense - it either works or it doesn't. Clearly it doesn't. Adding a long pipe isn't a cure if there's an ongoing pressurisation issue, a separator is required along with a return path for the oil to the gearbox. Sadly that is not a simple fix.

I presume they didn't detect this in the Asian cars because the motor/gearbox are different.

If they are different, why are they different and why was the "European" version not tested sufficiently to identify the issue?

The undertray is a separate issue and has its own thread. MG have said they will manufacture a new undertray but have not said when or whether they will retrofit.

The issue is more rectify or replace. Little of either appears to be happening at present.

 

[tsedge]

I'm being dense - it either works or it doesn't. Clearly it doesn't. Adding a long pipe isn't a cure if there's an ongoing pressurisation issue, a separator is required along with a return path for the oil to the gearbox. Sadly that is not a simple fix.

If they are different, why are they different and why was the "European" version not tested sufficiently to identify the issue?

The issue is more rectify or replace. Little of either appears to be happening at present.

I don't know if there is a pressurisation issue, first I heard of that. The bulletin just mentions the addition of a long pipe as the fix but they may have made other changes. Without gearbox design schematics and detailed technical specs, we have no idea what the detailed cause is.

It common that Asian model cars have a different spec to EU/UK because they are built to a different price/feature point. I don't know if this is what has happened but it wouldn't be surprising. The European version may have been a minor change of spec that they thought didn't justify re-testing. The oil level seems to be different, so that implies some changes.

Agreed that nothing much seems to be happening about the undertray and it should be addressed.

 

[WalkingBootWeather]

It common that Asian model cars have a different spec to EU/UK because they are built to a different price/feature point.

I'm not convinced this is the case tbh. Logically it is not worth a manufacturer's while to design, tool, build, store and manage an inventory of alternative core parts and to deal with increased failure rate of the inferior design. It seems to be more likely that difference in environmental conditions between Chinese and European markets are the cause of the problem only becoming apparent here.

 

[tsedge]

I'm not convinced this is the case tbh. Logically it is not worth a manufacturer's while to design, tool, build, store and manage an inventory of alternative core parts and to deal with increased failure rate of the inferior design. It seems to be more likely that difference in environmental conditions between Chinese and European markets are the cause of the problem only becoming apparent here.

Could be. We are only guessing here. It certainly HAS been the case in the past but as the Chinese market matures, it is likely they would all become common parts.

Edit: China is huge and they have all climates we have and more, so not personally convinced that is the reason.

 

[WalkingBootWeather]

China is huge and they have all climates we have and more

This is true. When I said environment I really meant the operating environment which includes things like condition of roads, amount of traffic, average speed, typical driving profile etc.

If many of the cars sold in China are used in congested cities, at relatively low speeds, and many of the British cars have been driven at higher speeds up and down motorways we might expect to see different pattern of failure even though components are the same.

 

[tsedge]

If many of the cars sold in China are used in congested cities, at relatively low speeds, and many of the British cars have been driven at higher speeds up and down motorways we might expect to see different pattern of failure even though components are the same.

Apparently they have 104,000 miles of motorway and we have 2,300! So maybe, maybe not!

 

[WalkingBootWeather]

Yep. Looks exactly the same driving conditions as UK

 

[Fogey]

I agree with and understand what you are saying I think the best plan of action would be to speak with your dealer.

As we know and have done for some while there is good and not so good in the dealer network, and it appears lots of them are coming at this issue in different ways so that’s why I say speak to them in the first place ( God I’m beginning to sounds like someone from MGs head office ) but it’s all you can do as far as I can see at the moment.

Just popped into the POLL results that was started by tsedge on the 11th of this month we now have,
50 votes,
25 have or have not seen any leaks,
21 have a leak but don’t yet know where from
So not every car has leaks our car is one of them so far but not many miles done as yet
Les

Seems like it's going to be a problem for just about all MG4s, not just the "few" that MG seem to be assuming (as one could conclude by their behaviour in not implementing a recall). I suppose the word "recall" is something to be avoided if you can, as a manufacturer.

 

[Harry 17]

Time to comment on all the YouTube reviews maybe?

 

[Fogey]

There is still something that doesn't add up from an engineering perspective.
If all UK cars come out of the factory with the same oil level and breather design there is nothing arbitrary about whether a problem should manifest. There must be a variable that's occurring at their end and the only thing that comes to mind for me is how much oil they put in the gearbox at its first fill.

Haven't there been reports here of reduced fill being implemented (specifically 0.9l to 0.7l) - to no avail?

 

[Deleted member 9692]

Haven't there been reports here of reduced fill being implemented (specifically 0.9l to 0.7l) - to no avail?

Mine was refilled with 0.7 litre and still leaked when road tested

 

[Sloucher]

I really don't see the point of all this conjecture over what does and what does not cause the oil leak. We're all aware by now that there IS an issue with the oil breather, but until either someone has their MG4 modified and can definitively explain whether or not the modification works or someone in a position to explain the design change does just that, we're all just tossing guesswork around.

 

[Harry 17]

I really don't see the point of all this conjecture over what does and what does not cause the oil leak. We're all aware by now that there IS an issue with the oil breather, but until either someone has their MG4 modified and can definitively explain whether or not the modification works or someone in a position to explain the design change does just that, we're all just tossing guesswork around.

Hallelujah

 

[AndyM]

I'm not sure where this leaves me that had the leak but after a refill there haven't been any further signs yet. I guess I'll be going back to the dealer in a couple of weeks to see what's happening.

 

[Deleted member 10041]

Had an email from my dealer today, not got my car yet, he was updating me about the breather fix for the oil leak. I had sent an email saying I was aware of the leak could he keep me updated.
Fair play to Perth MG been really good with their communication so far