MG4 Reduction Gearbox Oil Leak

[Ian Key]

Somebody on Faceache has posted this reply at 16:49 today (28/10/2022) from his dealer when asking about the oil leak. I have removed the names.

 

[Baz]

Somebody on Faceache has posted this reply at 16:49 today (28/10/2022) from his dealer when asking about the oil leak. I have removed the names.
View attachment 12206

The part ( it is neither the cause nor the solution to the problem ) gets me so what is the solution.

 

[Ian Key]

The part ( it is neither the cause nor the solution to the problem ) gets me so what is the solution.

I think they are implying that the breather pipe is not the cause of the oil leak so replacing it won't be the cure.
It looks like MG are sticking with the overfilling the transfer box is the problem so taking some out is the solution.

 

[Baz]

I think they are implying that the breather pipe is not the cause of the oil leak so replacing it won't be the cure.
It looks like MG are sticking with the overfilling the transfer box is the problem so taking some out is the solution.

nope didn't work on mine still leaked. Waiting for new breather.

 

[Fogey]

Oh dear.

 

[tsedge]

I think they are implying that the breather pipe is not the cause of the oil leak so replacing it won't be the cure.
It looks like MG are sticking with the overfilling the transfer box is the problem so taking some out is the solution.

Yes, I think it is poorly worded. The MG bulletin I have says that the breather is a fix for the problem, otherwise why bother? But some cars had the wrong level of oil too.

However, this sort of implies that they won’t fit the new breather at the factory, which would be odd.

 

[Bonny 865]

nope didn't work on mine still leaked. Waiting for new breather.

No didn't work on mine either

 

[Les burrows]

whereas a combination of the original breather plus a less than normal oil level resulted in no leakage

Can’t agree with you there Alb, it didn’t, there are several owners here who have had the oil removed and the gearbox refilled to a lower level and have still got a leak after.

it will be a few weeks yet until the new parts arrive and it will be interesting to see if them cars that are still have a leak after the breather has been changed or not.

And to owners would have a new breather fitted please ask how much oil has been put in the gearbox after fitting it.
If the breather is the problem and the fix is to change it then the correct oil levels of 0.9ltrs should be replaced in my view.
We will see.
Les

 

[AndyL61]

I have a theory. The oil, regardless of the amount ,it seems is coming out of the breather. That suggests to me that the breather is in the wrong place , it is in thr direct line of where the oil is thrown , hence it leaks out. A breather should be in a place away from where the oil is thrown by the gears so that it allows gasses to flow but never gets directly subject to the oil being thrown around the cavity. So I think the long term solution would be a re designed gear casing with the vent in a better position. Just a thought !

 

[Alb]

Can’t agree with you there Alb, it didn’t, there are several owners here who have had the oil removed and the gearbox refilled to a lower level and have still got a leak after.

I said it was what I could visualise as a rational explanation, not what actually happened. Besides, we have no knowledge of how accurately a 0.7 litre fill might have been determined so the margin between problem/no problem might be incredibly fine. All conjecture of course

 

[CraigMcKMG4]

Somebody on Faceache has posted this reply at 16:49 today (28/10/2022) from his dealer when asking about the oil leak. I have removed the names.
View attachment 12206

Ah it’s a placebo breather. Words fail me!

 

[Archev]

I have a theory. The oil, regardless of the amount ,it seems is coming out of the breather. That suggests to me that the breather is in the wrong place , it is in thr direct line of where the oil is thrown , hence it leaks out. A breather should be in a place away from where the oil is thrown by the gears so that it allows gasses to flow but never gets directly subject to the oil being thrown around the cavity. So I think the long term solution would be a re designed gear casing with the vent in a better position. Just a thought !

Interesting speculation.
I’ve not been following this breather story very closely as I’ve no real interest in the “four” as I prefer the estate car values of the “five”.
However I once bought a second hand Daihatsu three cylinder car for my daughter. It was very Smokey so I removed the cylinder head to check for wear and found everything to be in very good condition. I replaced the valve stem oil seals and gaskets during reassembly. It was still a very heavy smoker. After much head scratching I discovered that the breather pipe elbow fitting on the rocker cover had been fitted 180 degrees out. Simply turning it round to face the other direction stopped it scooping up excess oily throw off the rockers. (The other end of the breather tube was connected to the air filter which meant rather than an oil leak it was in this instance burning the oil laden air. )
Is it possible for the MG 4 ‘s breather assembly to be fitted differently in some instances???
Sincere apologies if this is a total red herring ramble ?

 

[Ian Key]

I said it was what I could visualise as a rational explanation, not what actually happened. Besides, we have no knowledge of how accurately a 0.7 litre fill might have been determined so the margin between problem/no problem might be incredibly fine. All conjecture of course

Agreed. The difference between 0.9ml and 0.7ml is about 3 egg cups which could easily be left smeared around the transfer box and gears.

 

[Les burrows]

I have a theory. The oil, regardless of the amount ,it seems is coming out of the breather. That suggests to me that the breather is in the wrong place , it is in thr direct line of where the oil is thrown , hence it leaks out. A breather should be in a place away from where the oil is thrown by the gears so that it allows gasses to flow but never gets directly subject to the oil being thrown around the cavity. So I think the long term solution would be a re designed gear casing with the vent in a better position. Just a thought !

Major job but you might well be correct
Les

 

[Ian Key]

If you thought the MG4 had a transmission problem spare a thought for Kia and Hyundai owners. They have issued a recall for 112,000 cars because the cars loose all power with a 20 to 30 second warning because of a manufacturing fault with the dual clutch gearbox.

 

[Steve Chope]

Ah it’s a placebo breather. Words fail me!

Absolutely!

 

[Fogey]

If you thought the MG4 had a transmission problem spare a thought for Kia and Hyundai owners. They have issued a recall for 112,000 cars because the cars loose all power with a 20 to 30 second warning because of a manufacturing fault with the dual clutch gearbox.

Yes, another reason to avoid ICE cars if you want automatic transmission (all flavours of which have their own disadvantages - reliability being one of those of the dual-clutch offerings).

 

[AndyL61]

If you thought the MG4 had a transmission problem spare a thought for Kia and Hyundai owners. They have issued a recall for 112,000 cars because the cars loose all power with a 20 to 30 second warning because of a manufacturing fault with the dual clutch gearbox.

I can only speak from experience but I have had 2 Ioniq hybrids with 100% reliability. Only reason I ordered MG 4 is because Hyundai do not do an affordable EV that I like.

 

[Macadoodle]

Yes, another reason to avoid ICE cars if you want automatic transmission (all flavours of which have their own disadvantages - reliability being one of those of the dual-clutch offerings).

Indeed. The complexity of today's ICE transmissions is horrendous, all simply because a fossil motor has such a narrow power and torque band, electric motors are so cool in comparison- one ratio ? no probs, I can work with that ( says a motor )

 

[wiz043]

Yes, another reason to avoid ICE cars if you want automatic transmission (all flavours of which have their own disadvantages - reliability being one of those of the dual-clutch offerings).

In fairness it is only the dual clutch gearboxes that have failed in SOME Ford Focus, Hyundai, VW's and a few other related brands and in many cases it was because owners had no idea how to drive them without burning out clutches. I had a Renault Clio RS 200 (hot hatch) for many years with a dual clutch auto and had no issues with it because you need to drive them like a manual car with an auto option and not allow them to 'creep' in traffic or not allow the transmission to hold the car stopped on a hill but use the brakes in the same way you would preserve the clutch on a manual car.
Also there have been very few dramas with torque converter and CVT trannies over the years in ICE vehicles.
I love the MG4 but time will tell whether the 'transmission' will hold up over time.