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Tesla SDU temperature sensor loose

Posted: Thu Sep 07, 2023 3:37 pm
by modellfan
Hello all,
I was just measuring my motor as Damien did for the large Drive unit and recording a video to have all the documentation how to do it on the small drive unit.
However, when I opened the inverter housing to my surprise, I found a little bit of oil at the bottom. I tink this is not how it’s supposed to be? I’m a little bit wondering as the water has its own cooling port .Image

Re: SDU Oil in inverter ?

Posted: Fri Sep 08, 2023 8:40 am
by modellfan
After watching some SDU disassembly videos I am pretty sure , that this is not normal. It was just a few spoons of oil and only on the motor side of the inverter housing. The Inverter itself is fully dry. As my temperature sensor seems to be loose, that might be the reason.

Did I get a SDU with defect from factory ? Didn't look like it was opened before.

Re: Tesla SDU temperature sensor loose

Posted: Sun Sep 10, 2023 1:46 pm
by modellfan
A little bit further in my investigation:
[media] [/media]

I would say , I 3d print a ring eliminating the play . And I test it after some minutes of running, if it’s not leaking anymore.

Any opinions on this ?

Re: Tesla SDU temperature sensor loose

Posted: Sat Jun 07, 2025 9:10 pm
by Steve16
Had a similar problem on my SDU. Discovered the temperature sensor plug was not fully seated. From the inverter side, the plug cannot be completely pulled out because of a stop. When out as far as it will go, you can feel the o-ring engaged in the hole. Pushed further in, the o-ring disengages. Mine was not far enough out to engage the o-ring. The C-clip was in the outer 2 flat spots on the plug. It goes in the narrow slot further down, which is only accessible when the plug is fully out. When correctly assembled, the plug sticks out roughly 3/4 in beyond the plastic housing.
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