MG4 Reduction Gearbox Oil Leak

[Alb]

OK check valve maybe the wrong term here but some sort of baffle that would be designed to pass air not great globs of oil ....all speculation of course

I could imagine something like this although under any normal circumstance the oil should be nowhere near the breather itself.
Credible reasons why that might occur in practice include too much oil of course plus foaming.

 

[tsedge]

True, but as we say oop north - I'm swithering. But will watch and wait for now

Give it a bit longer, we are learning more.

The grey colour some are seeing does concern me, that is highly unlikely to be good at such a low mileage. I would like a statement on that from MG too.

 

[Jester27]

Someone posted on the MG Facebook group that theirs is apparently fixed.

 

[Taq]

no one’s shown me the oil, so it could be any colour I’m just happy if it stays where it’s meant to be.

 

[Fogey]

Give it a bit longer, we are learning more.

The grey colour some are seeing does concern me, that is highly unlikely to be good at such a low mileage. I would like a statement on that from MG too.

Maybe the drain plug isn't magnetic? Nevertheless, not good, coupled with the oil loss.

 

[tsedge]

Maybe the drain plug isn't magnetic? Nevertheless, not good, coupled with the oil loss.

Maybe. It is the low mileage that is the worry but maybe the breather problem causes a colour change somehow?

 

[Taq]

no one’s shown me the oil, so it could be any colour I’m just happy if it stays where it’s meant to be.

Was gonna check underneath today but it’s done nowt but rain here for 3 days straight, I’ll starting wondering about swapping it for a boat If it carries on much longer.

 

[Lovemyev]

but maybe the breather problem causes a colour change somehow?

Can't see the connection there to be honest .

 

[tsedge]

Can't see the connection there to be honest .

Bit of googling reveals that grey colour can be caused by water getting in (milky or otherwise) and a faulty breather might cause this and water might cause apparent overfilling.

Sparkles in the oil is the sure sign of metal fragments.

 

[Ian Key]

Bit of googling reveals that grey colour can be caused by water getting in (milky or otherwise) and a faulty breather might cause this and water might cause apparent overfilling.

Sparkles in the oil is the sure sign of metal fragments.

Perhaps with the dropped under tray acting as a scoop it's causing moist air to be around the breather and gets sucked in

 

[Kithmo]

Just to put it out there, I found a video of the car which showed an exploded diagram of the motor. The Gear Set must be oil tight between the Electric Motor and Housings probably with a lip seal or mechanical rotary seal. When Motor running then they must be some windage from this in the motor housing which if the seal is not fitted or seated correctly would cause this windage air pressure to escape into the gear train housing and causing an overpressure. Hence oil spilling out of Breather. A good test would be to fit a remote pressure sensor in the breather plug and take some pressure readings when motor running and compare to cars with no leaks. This could be done on a rolling road in the garage. The bad side is if it was a seal problem then oil may be escaping into the motor end which would be dangerous. Really hope MG are aware of the implications of this fault.View attachment 11933View attachment 11934View attachment 11935

I thought the motor ran in the same oil as the transmission like the Toyota Prius one does.

 

[Thorpey]

Perhaps with the dropped under tray acting as a scoop it's causing moist air to be around the breather and gets sucked in

That's a really good point, combined with cold damp air maybe the reason this isn't Europe wide

 

[Taq]

If the breather is faulty does anyone know;

- exactly where it’s located as when I was with the MG mechanic he wasn’t even sure

- exactly where the oil pushed out would be deposited (on the motor or somewhere behind it, I.e. is there a pipe or just a static valve on the motor?)

Reason I’m asking is mine was passed as clear yesterday as the oil underneath id spotted the day after the original oil leak / level fix wasn’t apparent on the motor/gear itself, but the oil I photographed was leaching from the seam in between the rear floor panels/lower section of bumper.

The conclusion was that it was just left over oil that had been missed possible on the lip of lower bumper cover, It’s only a very narrow space so I could see how easily it may have been missed when they cleaned it.

If however a breather pipe runs out of the back of the motor there could be more going on, hope not and it’s back next week to be rechecked, but give we couldn’t see where the breather even was it would be nice to be sure that area is checked next week too.

It didn’t really help having so much grimly surface water on the roads yesterday on the run up to Leeds that surface(s) where the oil was seen had been pretty much sodded on the way there leaving nothing behind to trace back. So glad I’d date stamped pics of it (#get the snaps)

 

[Deleted member 9692]

If the breather is faulty does anyone know;

- exactly where it’s located as when I was with the MG mechanic he wasn’t even sure

I believe credit for this photo goes to @Hallix73 - and I think the breather is the part I’ve circled. The techs I have been dealing with indicate that it is not easy to view, but they can feel the oil wetness when they put their hand around and on top of the gearbox. They know for sure mine is leaking from the breather apparently from the dye they used, they tell me they are 100% it’s coming from breather.

 

[Lucas Roper]

Some positive news from the MG EV Facebook group.

 

[beefyj]

Some positive news from the MG EV Facebook group.

Post #640 I think on this thread

 

[Lucas Roper]

Post #640 I think on this thread

Oops my bad! Don’t know how I missed that!

 

[Fogey]

Can't see the connection there to be honest .

Well, if too much oil is lost, then the gear train will be deprived of lubricant, and the resulting grinding of meshed teeth could cause tiny metal fragments to become suspended in the oil, causing the grey colouration.

 

[Taq]

View attachment 12058

I believe credit for this photo goes to @Hallix73 - and I think the breather is the part I’ve circled. The techs I have been dealing with indicate that it is not easy to view, but they can feel the oil wetness when they put their hand around and on top of the gearbox. They know for sure mine is leaking from the breather apparently from the dye they used, they tell me they are 100% it’s coming from breather.

If that’s it and it was leaking I’d think there would be oil all over the bottom of the casing which it definitely wasn’t when it was checked yesterday ??

 

[Taq]

If that’s it and it was leaking I’d think there would be oil all over the bottom of the casing which it definitely wasn’t when it was checked yesterday ??

Water ingress with oil, usually gives it a creamy beige colour.
Grey coloured oil would indicate a sign of metal / alloy is present.

The oil that was leaking from ours was pretty clear and had a bit of a yellow colour, didn’t look at all discoloured or cloudy (well assuming wiping if off the bottom would show this)