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So the failed seals have more in common with a pool pump seal than any automotive seal I've ever seen. Basically a spring pushing a piece of ceramic and graphite together to form a seal.
So making a custom seal is extremely difficult, and even then isn't likely to last any longer than the OEM seal. And Audi will not sell you these parts.
This does go a long ways to explain why some cars experience motor failure pretty early on and some make it to 90K miles before failure like mine. Seals like this don't fail gradually or gracefully. My car filled its catch can 1/4 of the way in the 5 minutes I took to move it into my '****s broken' bay of the garage. So if you have this seal failure your motor life is probably measured in minutes, not hours.
So what are we do to? This failure is inevitable on 100% of Etrons over a long enough timeline.
Since I got nothing to lose I'm going to eliminate rotor cooling on my rear motor. That's probably not great for sustained high power output but I don't tow with my etron anymore anyway.
The downside is my rotor might unexpectedly overheat someday and destroy the motor, but these motors are already death curious so I don't see that as much of a change.
Updates soon on how to reroute coolant flow in the motor.
figure out return path for coolant that makes it into coolant catch can :-), with one way valve that uses venturi effect to suck the coolant out of it back into coolant pump return line?
Last edited by nadrealista; 04-05-2024 at 01:26 PM.
That's a pretty poor take when the vehicle shouldn't have design flaws in the first place.
All, or at least many vehicles can have flaws, and unfortunately many of those flaws express themselves with miles and years of service.
You are obviously mechanically technically astute. I used to be but now due to age and indifference I'm no longer interested in performing major repairs on our vehicles, and I dare guess that the vast majority of your 'average' owner is the same way.
I made a vow decades ago to never own an expensive German car out of warranty, or with the 'comfort' of a high quality extended warranty. I think that philosophy can be extended to the majority of BEVs, as we simply haven't had enough experience to see how most of them hold up as they 'mature.
Spending say $5,000 to extend the Audi warranty out to 6/7 years and 75K-100K miles seems like a really good investment to me.
figure out return path for coolant that makes it into coolant catch can :-), with one way valve that uses venturi effect to suck the coolant out of it back into coolant pump return line?
I was thinking this was a good idea and went out to stare longingly into the eyes of my motor to try and understand why they didn't do that.
it's because when the seals fail coolant gets pumped into the transmission. which explains where all my coolant went. And probably means a small amount of coolant finds its way into the transmission during normal operation.
Hans, Klaus, if you're out there somewhere reading this, I want you to know I'm very disappointed in you.
So the plan right now is to CNC machine a new one of these, I'm going to call it the encoder cover.
The two options that have to be sorted out are whether to air cool the rotor, which would be a shame since it'll put limitations on vehicle performance.
hm that is very interesting, transmission is sealed off from the motor no? or motor housing acts as the other side of the transmission case? so your transmission was overfilled then with mix of gear fluid and coolant, was it making any kind of noises?
I think these motors get hot under load (100 C +) - lot of power going through them so air cooling might be non-starter...
This is what we need on the forum! Question, what’s the plan to replace or repair the bearing though. Even air cool etc, I suppose a working bearing is still needed?
That's a pretty poor take when the vehicle shouldn't have design flaws in the first place.
That's a flawed premise. Not all motors fail, in fact the best info available suggests that only a fraction of them fail. Although clearly the number is too high. But there are many examples of used etrons with a perfect history at 60k, even 80k miles. A "design flaw" would result in 100% failure at some point in time, but this is not what's happening.
Best info suggests that changes in the motors have occurred all through the etrons' life which were intended to improve reliability. Liquid cooling is absolutely necessary not only in the motor but also in the connecting cables and the ECU unit attached to the motor. There are schematics available via web searches that detail the cooling systems. The MOST remarkable thing about these complicated systems is that they don't fail more often.
This does go a long ways to explain why some cars experience motor failure pretty early on and some make it to 90K miles before failure like mine. Seals like this don't fail gradually or gracefully. My car filled its catch can 1/4 of the way in the 5 minutes I took to move it into my '****s broken' bay of the garage. So if you have this seal failure your motor life is probably measured in minutes, not hours.
So what are we do to? This failure is inevitable on 100% of Etrons over a long enough timeline.
Would you say there's anything in this design that is (more) prone to failure due to prolonged running time? Both of mine failed during or right after long drives and I've been wondering whether having less frequent cool-downs can somehow induce failure. I would think there should not be much in the way of temperature variation, with the coolant running past these seals.
Do you know what exactly is failing? Is it the rubber ring or the ceramic-to-graphite interface? I would think there's no way there would not be some seepage between those two surfaces and over time a bit of build-up would develop, destroying the seal.
04-05-2024, 10:28 AM
