Coolant Delete

[Rakesh Suresh]

Hello, Rakesh. Bouncing off of what asavage said. It really depends, and without a proper photo of the speed sensor.

Here is the speed sensor area. The speed sensor is clean. I forgot to take the picture of colorless moisture before I wiped it with a rag a week ago. Since then I don't see any more moisture on it.

 

[alflash]

Thanks for the answer!
Mini-question. Do I understand correctly that you do not rewind the stator?
https://alflash.com.ua/2019/to_rav4ev/stat2.jpg

 

[Konduit EV]

You are correct, we do not rewind the stator. As you and I know that is a whole different beast, especially when it comes to labor hours. Luckily for us here at Konduit EV, we have a few stators in good health that we can use if a replacement is needed. If stators become scarce then we would look at the alternative method of rewinding the stators but at the moment it just isn't feasible. Im glad to answer your questions. Keep them up if you have any more!

Phone # (760) 798 0342

1315 Hotspring Way Suite 102
Vista California
92081

Jacob Shellnutt
Konduit Ev
Co Owner and Technician

 

[Konduit EV]

View attachment 826

Here is the speed sensor area. The speed sensor is clean. I forgot to take the picture of colorless moisture before I wiped it with a rag a week ago. Since then I don't see any more moisture on it.

Hey Rakesh! It looks pretty clean, I don't see any rust or corrosion at least in and around the speed sensor hole. I'd advise you not to drive the car as that will only exacerbate the problem and will cause even more coolant intrusion. Get that coolant delete that you have installed immediately. Coolant can (and will) leak past the seal even if you don't drive the vehicle once that seal has started leaking. Also i'd recommend you take a photo with the coolant manifold taken off and posting it to this thread, so we can see how it looks at least just right by the speed sensor gear.

Phone # (760) 798 0342

1315 Hotspring Way Suite 102
Vista California
92081

Jacob Shellnutt
Konduit Ev
Co Owner and Technician

 

[asavage]

If your reluctor chamber has no vent hole (and it appears that it doesn't), then you have a better chance of coolant not having migrated to the stator cavity; with no vent, it can only get there via the outer rotor bearing -- coolant migrates through its seals -- which if compromised is relatively easily replaced, though the LDU does have to be dropped enough to pull the rotor cap off (see my LDU Special Disassembly Tools post) and to provide clearance for a bearing puller .

If you don't have the original rotor bearings -- which are steel -- and have a Reman or rebuilt LDU, the hybrid bearings seem to have good service life. The original rotor bearings suffered low service life (in general: exceptions do exist) due to the poor service life of the original Aegis rings ("brushes") that were supposed to drain stray induced rotor currents to chassis ground, but didn't in a lot of cases. But coolant in either of them doesn't work well, in any case!

 

[alflash]

Hello Alflash, I apologize for the delayed response. I'm stretched thin at the moment but would like to provide those photos I promised you. As expected, just about everything is kaput. The inverter board is corroded beyond repair and the connector board has a small amount of delamination with corrosion underneath the dielectric compound used to encapsulate the board. The stator also has zero isolation, so the diagnosis is that which we all suspected. It is yet another dead LDU, total loss except for the gear set.
Phone # (760) 798 0342
1315 Hotspring Way Suite 102
Vista California
92081
Jacob Shellnutt
Konduit Ev
Co Owner and Technician

Thanks for info!

Excuse me, to the questions.
Is this the inverter "brains" board of that vehicle from your video with the G48 liquid waterfall?
What device do you use to check the insulation resistance between the stator windings and its housing?
Please show a photo of the inner surface of the side cover of the motor.

 

[Konduit EV]

Good Morning Alflash. Yes this is the same motor the video with the coolant pouring out of the inverter housing. Oddly enough, the contactors would still click on but would immediately click off and take the car out of ready. Before I drained all of the G48 and saw it coming out of the inverter, I thought the motor would still be salvageable purely because of the contactor click. Regarding the device used to test isolation in the stator, we use the Klein tool part number ET600, set at 500v. Also here are some photos of the side cover.

 

[alflash]

Good Morning Alflash. Yes this is the same motor the video with the coolant pouring out of the inverter housing. Oddly enough, the contactors would still click on but would immediately click off and take the car out of ready. Before I drained all of the G48 and saw it coming out of the inverter, I thought the motor would still be salvageable purely because of the contactor click. Regarding the device used to test isolation in the stator, we use the Klein tool part number ET600, set at 500v. Also here are some photos of the side cover.

Thanks for answer!
As I understand it, the car was in a faulty condition for a long time. Why are there no such traces of liquid in the stator on the side cover?
https://alflash.com.ua/2019/to_rav4ev/side_covert.jpg

https://alflash.com.ua/2019/to_rav4ev/madlen.jpg
https://alflash.com.ua/2019/to_rav4ev/stat3.jpg

Am I right in seeing that this engine did not have such a brush to protect the bearings from electrical erosion due to high-frequency interference?
https://alflash.com.ua/2019/to_rav4ev/_2041s.jpg

https://alflash.com.ua/2019/to_rav4ev/brush_.jpg

 

[asavage]

Vlad, the rotor cap that you showed above look as if the coolant was leaking, then somebody was topping up with plain water. That corrosion does not look like typical corrosion from coolant alone -- the coolant provides some corrosion protection.

Or, perhaps, yours was sitting with coolant leaked for many years?

 

[Rakesh Suresh]

Also i'd recommend you take a photo with the coolant manifold taken off and posting it to this thread, so we can see how it looks at least just right by the speed sensor gear.

Removed the manifold. Here are the pics and video. There appears to be some stuff there that looks odd, but I don't know if that's corrosion from the leak.

https://1drv.ms/f/s!AoMSicNQxi7y5kuyn02C_KyKZl-g

 

[Lido]

Removed the manifold. Here are the pics and video. There appears to be some stuff there that looks odd, but I don't know if that's corrosion from the leak.

https://1drv.ms/f/s!AoMSicNQxi7y5kuyn02C_KyKZl-g

Other than the crud behind the gear it looks pretty clean. Hopefully one of the pros can tell what that is and if it's an issue to try to deal with.

 

[Konduit EV]

Any bearing noise? That's a good indicator on whether or not coolant has started migrating through the bearing. Although it would be more likely for the coolant to go through the breather hole in your reluctor chamber, it's still entirely possible for it travel through the bearing. As far as that yellow/brown build up you are seeing, that is grease that has made its way outside of the rubber bearing seal. I do not see much corrosion, nor crystallization of coolant due to the evaporation of the water out of the coolant. In my opinion, treating this as if it were my own vehicle, I would be comfortable just putting on the coolant delete as long as there is no bearing whine, as that's a problem that will only worsen with time. Also do your absolute best to get all of the coolant and gunk out from behind the reluctor wheel.

 

[asavage]

Agree with Jacob. You have, unfortunately, an early/non-Reman unit that still has an open reluctor chamber vent, so any coolant leak aerosolizes and makes its way into the stator cavity so easily. And moisture in the LDU doesn't go anywhere, it continues to corrode and degrade the stator windings; there is no airflow and almost no air migration into/out of the the LDU, so it's there "forever", until it's used-up (has been converted to rust, etc.).

Since it's impossible to remove moisture in the stator cavity without removing the entire LDU and removing at least the rotor end cap, you have a choice to make: run it, or commit to a lot more work. Tough call.

 

[Rakesh Suresh]

Thanks @Konduit EV @asavage

Any bearing noise

I don't know how this would sound. Do you happen to have a video of it? In general, I have not noticed any noise (except for the kind-of electromagnetic hum at low speeds which I think is normal?)

And moisture in the LDU doesn't go anywhere, it continues to corrode and degrade the stator windings; there is no airflow and almost no air migration into/out of the the LDU, so it's there "forever", until it's used-up (has been converted to rust, etc.).

Ouch. Any idea how many years would it take to start seeing noticeable issues? Pardon my dumb question. If there is a way for moisture to get in can't the moisture get out from the same place?

 

[asavage]

"The same place" the coolant came is is the seal you just removed, and once it got past the seal, it was aerosolized (I do like that word) and migrates through that reluctor chamber vent hole, from whence it won't come back. To remove any moisture on the other side of that vent, the rotor end cap has to be removed, and the rotor removed. I did that job for the same reason as yours: I had coolant leakage on my Reman LDU and while I didn't have a vent hole like yours, still there was plenty of coolant on the stator side of that cap.

There is a case vent and a gearbox vent, both on top near the center, but they only equalize pressure due to the inverter heating up, and they incorporate a teflon composite filter (sort of a mesh) that's specifically designed to prevent water getting through. Water that's in there is going to stay in there.

If you weren't hearing anything unusual before, and you've owned it long enough to know what it sounded like some miles ago, then the bearing is possibly OK for now. If it's never been touched, it'll have the original steel balls in the bearing and the ill-fated Aegis ring that didn't work for long, so at some point you'll have to replace both of the rotor bearings for the later (and more expensive) hybrid ceramic ball beaings . . . which moves the problem downstream to the pinion bearings and gears, but they seem to tolerate it better, or at least longer.

If you disassemble the LDU to remove the rotor and clean out the stator cavity, I recommend replacing the rotor's bearings; that's best practice. Esp. if you see an old Aegis ring inside when you remove the rotor.

The stator's HV windings isolation resistance goes down when exposed to water, and it gets worse. When it gets low enough, the BMS check at startup will fail, and it won't allow the contactors to close. Then you have to have the stator dried out by ReVolt in Arizona, and if they can dry out your stator, you're probably out around $4-8k. Plus R&R of the LDU, of course. Until recently, there was nobody advertising that they could dry out damaged stators, but ReVolt says they can now -- there's a lot more demand from Tesla MS/X owners recently

 

[Rakesh Suresh]

To remove any moisture on the other side of that vent, the rotor end cap has to be removed, and the rotor removed.

Thanks for the explanation ! So, it's a one way trip for the moisture unless the LDU is opened up.

The isolation resistance is available from the Tpd. Can that be monitored at regular intervals to assess deterioration over time?

I don't have resources for an ldu removal at the moment but time may free up a bit in the future. I will go ahead with coolant delete for now but trying to see what I can do to get advance warning before a catastrophic failure so that I can plan for the time commitment.

 

[asavage]

The isolation resistance is available from the Tpd. Can that be monitored at regular intervals to assess deterioration over time?

Yes, but the stator isn't powered with HV until you have it in "gear" and foot off the brake pedal, so you can't check it just sitting in Park.

 

[Rakesh Suresh]

Had a weird thing happen. The o ring which I had taken out, just expanded so much in 24hrs that it no longer fit. I tried boiling it in water and used a heat gun to shrink it but it barely made a difference

 

[alflash]

... The isolation resistance is available from the Tpd. Can that be monitored at regular intervals to assess deterioration over time?

Note. The insulation resistance between the stator windings and the stator housing is not the Isolation Resistance* parameter in the diagnostic program.
A three-phase voltage is supplied to the stator windings**, controlled in amplitude and frequency by an inverter.

* https://alflash.com.ua/2019/to_rav4ev/isol_resist.png
** https://alflash.com.ua/2019/to_rav4ev/inverter1.png