RDU/LDU coolant bypass innovation

[NV Ray]

There has been a recent rear drive unit/large drive unit innovation/modification from both Tesla and QC Charge for 2012-2014 Tesla Model S (all) and 2015-2020 Tesla Model S and X, Performance versions only, rear drive motor only.

Tesla calls it their new "U" seal delete manifold version. QC Charge calls it coolant delete. Both are to mitigate the leaking seal issue with these drive units.

Are both innovations/modifications the same? My understanding is they are in that the coolant that is provided to the rotor/stator is bypassed so that the coolant goes directly to the 3 x ICBTs in the inverter and then through the gear box heat sink, then out.

Pros/cons? While the leaking seal issue is "bypassed", would then the rotor/stator risk failing due to no cooling? Or is that risk so minimal to offset the leaking seal issue?

Here's QC Charge link COOLANT DELETE Tesla Large Drive Unit

Pics are Tesla's invoice and drive unit label for similar revision.

 

[ucmndd]

There has been a recent rear drive unit/large drive unit innovation/modification from both Tesla and QC Charge for 2012-2014 Tesla Model S (all) and 2015-2020 Tesla Model S and X, Performance versions only, rear drive motor only.

A correction to your scope above: Tesla produced non-performance RWD cars until late 2017, all of which had the large rear drive units subject to the defect being discussed.

 

[NV Ray]

Update: For those visual learners, like me, this video (cued to start) by Prof Kelly explains the entire large/rear drive unit cooling process. It's my understanding that the coolant delete/seal delete manifold version simply stops the first path from inlet through rotor tube. The coolant path instead starts through the stator, then to the IGBTs in the inverter, then to the cooling nobs on the gear drive, and finally back out.

 

[NV Ray]

Pics are before and after.

 

[RevoltSystems]

We also have a kit to fix this issue.

 

[NV Ray]

We also have a kit to fix this issue.

Cost?

 

[Woodwinds]

Tesla Large Drive Unit (LDU) Coolant Bypass Kit “The Achilies Seal Fix” - Revolt Systems

Tesla Large Drive Unit (LDU) Coolant Bypass Kit "The Achilies Seal Fix" $499.00 This coolant bypass kit prevents the notorious issue of the rotor seal failing and flooding the drive unit, leading to catastrophic failure. If this happens, your entire motor and inverter can be destroyed, leading...

revoltsystems.com

$499

I'm starting to research options. I believe my car is in scope. 2016.5 S 75 RWD. 150k miles. So far car runs fine, but I want to keep it forever. Is it wise to ask Tesla to check it before the warranty expires?

 

[NV Ray]

Tesla Large Drive Unit (LDU) Coolant Bypass Kit “The Achilies Seal Fix” - Revolt Systems

Tesla Large Drive Unit (LDU) Coolant Bypass Kit "The Achilies Seal Fix" $499.00 This coolant bypass kit prevents the notorious issue of the rotor seal failing and flooding the drive unit, leading to catastrophic failure. If this happens, your entire motor and inverter can be destroyed, leading...

revoltsystems.com

$499

I'm starting to research options. I believe my car is in scope. 2016.5 S 75 RWD. 150k miles. So far car runs fine, but I want to keep it forever. Is it wise to ask Tesla to check it before the warranty expires?

You could ask Tesla to check out and unless there are any alerts, you'll be charged a disagnostics fee. Even, then there's no guarantees you'll have any out of warranty issue. It's a crap shoot.

 

[Fritchard]

Tesla Large Drive Unit (LDU) Coolant Bypass Kit “The Achilies Seal Fix” - Revolt Systems

Tesla Large Drive Unit (LDU) Coolant Bypass Kit "The Achilies Seal Fix" $499.00 This coolant bypass kit prevents the notorious issue of the rotor seal failing and flooding the drive unit, leading to catastrophic failure. If this happens, your entire motor and inverter can be destroyed, leading...

revoltsystems.com

$499

I'm starting to research options. I believe my car is in scope. 2016.5 S 75 RWD. 150k miles. So far car runs fine, but I want to keep it forever. Is it wise to ask Tesla to check it before the warranty expires?

I checked mine the week before warranty expired, there was clearly coolant on the speed sensor.
Booked it in for Tesla to confirm, after an unnecessary & ridiculous argument, they have agreed to replace it under warranty. Ready to collect today & hopefully I can get more than 8 years & 165k out of this motor (assuming it is revision U…if not, I feel there’s another argument!).

 

[NV Ray]

I checked mine the week before warranty expired, there was clearly coolant on the speed sensor.
Booked it in for Tesla to confirm, after an unnecessary & ridiculous argument, they have agreed to replace it under warranty. Ready to collect today & hopefully I can get more than 8 years & 165k out of this motor (assuming it is revision U…if not, I feel there’s another argument!).

Remember that you are currently past 8 years, there is no warranty on the replacement Tesla just installed. Also, did Tesla replace with a reman or new?

 

[RevoltSystems]

You could ask Tesla to check out and unless there are any alerts, you'll be charged a disagnostics fee. Even, then there's no guarantees you'll have any out of warranty issue. It's a crap shoot.

We just opened one of our motors on our shop car. The LDU was out of a 2020 with 36k miles on it. The seal had a failure already developing and the rear bearing was showing signs of corrosion and the snap ring was very rusty. This shows that even low mileage cars are susceptible to this failure. Tesla is now also offering a “U” revision with a similar bypass manifold to ours for some of the fixes but only for motors still under warranty.

 

[RallyeBart]

Tesla Large Drive Unit (LDU) Coolant Bypass Kit “The Achilies Seal Fix” - Revolt Systems

Tesla Large Drive Unit (LDU) Coolant Bypass Kit "The Achilies Seal Fix" $499.00 This coolant bypass kit prevents the notorious issue of the rotor seal failing and flooding the drive unit, leading to catastrophic failure. If this happens, your entire motor and inverter can be destroyed, leading...

revoltsystems.com

$499

I'm starting to research options. I believe my car is in scope. 2016.5 S 75 RWD. 150k miles. So far car runs fine, but I want to keep it forever. Is it wise to ask Tesla to check it before the warranty expires?

Hi Woodwinds. I’m new to this forum. And I’m kind of worried about this issue.

You say your car is “in scope” for the coolant leak issue. How did you determine that? It there something outlining affected LDU years, VINs, or whatever? If so, where do I find that?

It was my understanding that this is an issue on all LDU Model S vehicles until the time Tesla implemented their design change. Yes?
1) When did Tesla figure out there was an issue with coolant leaks? (Can somebody please point me to literature or posts?)
2) On what date/VIN did Tesla implement their factory version of coolant delete?
3) I presume remanufactured or serviced LDUs would continue to have this problem unless the coolant bypass solution was implemented?
4) Is this an issue Tesla could have seen at final test? Or is it invisible until the seal finally decides to wear out and start leaking?
5) Is Tesla owning up to this design issue? That is, are they recalling cars, or offering service credits, etc?

Thanks

 

[NV Ray]

Hi Woodwinds. I’m new to this forum. And I’m kind of worried about this issue.

You say your car is “in scope” for the coolant leak issue. How did you determine that? It there something outlining affected LDU years, VINs, or whatever? If so, where do I find that?

It was my understanding that this is an issue on all LDU Model S vehicles until the time Tesla implemented their design change. Yes?
1) When did Tesla figure out there was an issue with coolant leaks? (Can somebody please point me to literature or posts?)
2) On what date/VIN did Tesla implement their factory version of coolant delete?
3) I presume remanufactured or serviced LDUs would continue to have this problem unless the coolant bypass solution was implemented?
4) Is this an issue Tesla could have seen at final test? Or is it invisible until the seal finally decides to wear out and start leaking?
5) Is Tesla owning up to this design issue? That is, are they recalling cars, or offering service credits, etc?

Thanks

1. Unknown. Tesla hasn't said anything.
2. In the Fall of 2023 is when Tesla started introducing the U seal manifold delete version which superceded the T version. Pic is my recent proactive replacement.
3. Yes.
4. Sadly, the coolant leak is an issue from day one. Tesla's LDU is the same LDU as some older Mercedes EVs and Toyota RAV4 EVs which also had coolant leaking issues.
5. Don't know if Tesla is owning up to design issue. No on recalling cars or offering service credits.

My post Proactively replacing RDU/LDU

 

[j.harris]

5) Is Tesla owning up to this design issue? That is, are they recalling cars, or offering service credits, etc?

They are owning up to it by replacing the LDU under warranty. After the warranty expires it's your problem.

 

[NV Ray]

We just opened one of our motors on our shop car. The LDU was out of a 2020 with 36k miles on it. The seal had a failure already developing and the rear bearing was showing signs of corrosion and the snap ring was very rusty. This shows that even low mileage cars are susceptible to this failure. Tesla is now also offering a “U” revision with a similar bypass manifold to ours for some of the fixes but only for motors still under warranty.

Tesla also offers the U version for out of warranty owners. Here's mine.

 

[VxA=W]

The drive unit/battery warranty on my 2016 runs out June 18th. I've already scheduled service for June 5th, doing the MCU-2 update and inspect/service sunroof.

Do you think if I ask them to inspect the LDU for this issue, they will do so and if they find coolant evidence will replace it under warranty? Or do I need to inspect it first independently, report to them if coolant is seen, and take it from there?

I've done a fair amount of reading, and of course know my S is vulnerable to this, but still don't have a sense if it's 10%, 50%, or nearly all of them that end up with this problem.

 

[NV Ray]

The drive unit/battery warranty on my 2016 runs out June 18th. I've already scheduled service for June 5th, doing the MCU-2 update and inspect/service sunroof.

Do you think if I ask them to inspect the LDU for this issue, they will do so and if they find coolant evidence will replace it under warranty? Or do I need to inspect it first independently, report to them if coolant is seen, and take it from there?

I've done a fair amount of reading, and of course know my S is vulnerable to this, but still don't have a sense if it's 10%, 50%, or nearly all of them that end up with this problem.

I'd recommend inspecting your speed sensor for coolant independently and then report to Tesla according. Tesla could also inspect but will likely charge you. It's really easy to check yourself.

 

[VxA=W]

Thanks for that video, certainly an easy check. I have to find time and will look into proper jacking/jackstand points before I lift it. Wish I had access to a lift, might see if someone local would be willing to put it in the air for me to do this.

 

[NV Ray]

Thanks for that video, certainly an easy check. I have to find time and will look into proper jacking/jackstand points before I lift it. Wish I had access to a lift, might see if someone local would be willing to put it in the air for me to do this.

I just backed up on car ramps.

 

[Cheburashka]

The drive unit/battery warranty on my 2016 runs out June 18th. I've already scheduled service for June 5th, doing the MCU-2 update and inspect/service sunroof.

Do you think if I ask them to inspect the LDU for this issue, they will do so and if they find coolant evidence will replace it under warranty? Or do I need to inspect it first independently, report to them if coolant is seen, and take it from there?

I've done a fair amount of reading, and of course know my S is vulnerable to this, but still don't have a sense if it's 10%, 50%, or nearly all of them that end up with this problem.

Based on the design I think the answer is 100%, just a matter of how long it will take.

If your sensor is still dry then I would be looking at other avenues to get the coolant bypass done. Much cheaper than 6-7k down the road for a replacement.

Just my opinion.