Drive unit coolant leak, tear down/test/repair (hopefully)

[stang_shane]

You should never reuse o rings. They will not seal as well as new ones.

I would be guessing on the correct profile diameter and ID/OD. Tesla won't provide this information as it's part of the HV system.



Per Tesla doc
"The following will also void this New Vehicle Limited Warranty:
• Vehicles that have had the VIN defaced or altered or the odometer or other related system disconnected, altered or rendered inoperative so that it is difficult to determine the VIN number or actual mileage;
• Vehicles that have been designated, labeled or branded as dismantled, fire-damaged, flood damaged, junk, rebuilt, salvage, reconstructed, irreparable or a total loss; and
• Vehicles that have been determined to be a total loss by an insurance company"
https://www.tesla.com/sites/default/files/downloads/tesla-new-vehicle-limited-warranty-en-us.pdf

 

[stang_shane]

Car is back together and everything powered up just fine. I'm working on 3D printing the inverter power cable cover, somewhat of a combination of reusing the old broken piece and gluing on my 3D printed piece. Hopefully back driving in a few days.

 

[stang_shane]

Just another update, the car is back together and I took it for a little drive yesterday. I initially had a parking brake error, did not release. I simply put the car in park and back in drive and it released properly. I'm assuming due to the way I disassembled and reassembled, the parking brake needed to actuate first to reset. In order to get the parking brake back on (found out it didn't even need to come off until late), I needed to open the caliper. This is an electric motor driving the caliper in/out. So I used a 12v source to drive the caliper in slightly so I could fit the pads back on the rotor.

Secondly, I had a low coolant error message so less than 2-3 seconds. Without Toolbox to turn the coolant pump to bleed the system, I believe this was an air pocket being pushed out of the system, since the error code did not stay on. I will be checking the coolant level tonight to confirm the correct level again.

Overall, I've very pleased so far. Obviously my issue was one that occurred over time and I'm not expecting an immediate re-occurring error, but I'm confident in the repair.

I was able to glue together the orange cover over the HV cable connection, and I've 3D printed a reinforcing piece to glue onto the exposed side. I also did have to replace one of the o-rings on the HV orange cover, it was crimped in two spots from when Tesla did the install or previous service. I was able to use an o-ring from a local hardware store that was very close to the same size and fit the inverter case bore. (.125"x1") for future reference.

 

[DIYDanCars]

Nice work! So is your car working fine again?

 

[bart_dood]

One question, as I understand it the failure mode on the big motor is the motor bearings for the rotor are sealed with grease which eventually degrades, this degrades the bearings which start to have more run-out. The extra run-out stressed the teflon rotating coolant seal to the rotor, this seal then leaks coolant into the motor.

My fingers are crossed for you, but this might start leaking again. If I had the motor apart I would have put new bearings in and a new teflon seal, plus new O-rings.

There is a re-build thread of this motor on here from a Rav4 owner, you will find it really useful.

 

[stang_shane]

Nice work! So is your car working fine again?

That is correct...at least for the moment. I did not drive the car to work today, as I will be looking closer at the coolant, but it was definitely nice to have it on the road again yesterday.

One question, as I understand it the failure mode on the big motor is the motor bearings for the rotor are sealed with grease which eventually degrades, this degrades the bearings which start to have more run-out. The extra run-out stressed the teflon rotating coolant seal to the rotor, this seal then leaks coolant into the motor.

My fingers are crossed for you, but this might start leaking again. If I had the motor apart I would have put new bearings in and a new teflon seal, plus new O-rings.

There is a re-build thread of this motor on here from a Rav4 owner, you will find it really useful.

This would be two separate issues. My coolant leak was on the inverter side of the gear box, not the motor side. I've also seen the videos and write-ups on issues with the bearings, although mine makes no noise whatsoever. The coolant leak on my unit only have a few access points into the inverter housing. There are 3 passages through the inverter itself, as shown in the 6 openings on the inverter/gear box. Each passage has an in/out, these are sealed by 3 o-rings. Beyond that, the only possible entry point for coolant into the inverter is a crash in the gearbox passages, leading to the 3 passages or out of the 3 passages. Or, the aluminum housings that are part of the inverter were cracked, leading to coolant leaking to the inside of the inverter. After inspecting my unit, there was no coolant "inside" the inverter ans was mostly on the "back" where it mounts to the gearbox. So either leaking past an o-right, which is the most likely scenario, or it was leaking through a crack in the gearbox. I checked the gearbox multiple times and saw no cracks or apparent pathway where the coolant may have been flowing.

Most commonly I've seen that the worn bearings whine or growl. I do have the older style DU, so there is a greater potential for bearing failure than the later revisions. But I would hate to do the work and potentially cause an issue when I currently have no issues. Besides, this was easier than I expected and doing it again would be easier. I'm just glad I was able to do on the garage floor and by myself instead of a more complicated fix or paying Tesla to do the work.

 

[stang_shane]

WELL.....the car drove great for about 2 weeks until I got the same error. I already know what you're thinking or wanting to say. Yes, it didn't work but that doesn't mean I'm not going to try again. I've already taken the DU back out, disassembled the inverter to a level that I don't think it would come apart any further to check all the coolant passages. The coolant passages are clamshell pieces that the coolant run in and out of. I have a bunch of picture of everything apart, just need to get them uploaded here. Putting the unit back in tonight and hoping this is the correct fix. I did run water through the drive unit assembly before I removed the inverter, trying to determine where the leak might be coming from. I checked the inside of the inverter while letting the water build a small amount of pressure by blocking the exit and no leak. Also checked the area where the o-rings were and saw no leak. To be honestly, partly discouraging, but I build up a decent amount of pressure and still saw no leaking. But as I disassembled further, I'm no suspecting that the clamshell pieces might have been leaking. One of the plastic covers had coolant on it that met up directly to these clamshell pieces.

Picture to follow and I'll be sure to update on the potential repair success/failure.

 

[stang_shane]

Here's my method for removing in case anyone is looking for a nice technique on the floor. I basically cut a piece of plywood that reaches across the rear subframe. Then I jack up on the middle support of the subframe, with the 3rd jack to pitch the DU forward or backward.

 

[stang_shane]

Here's the additional work that I did on this repair. I believe that Phase A had a small leak on these clamshell pieces, at the corner. There is a plastic cover that goes over the end that bolts onto the gearbox. You can see this is one of my previous post (it shows the 3 copper AC leads out of the inverter). This cover had coolant on it near Phase A on this removal, and also had a little coolant on another part of this cover. Which leads me to believe...either the sealing surface with the o-ring, that I added sealant around leaked again or the clamshell pieces were leaking. Also, when I pried apart the clamshell, Phase A looked like the black sealant had coolant on it when I popped them open. Obviously this could have been part of the disassembly process, but Phase A looked different than B or C.

Hopefully this end up being the problem. But installed everything last night and the car is back running again.

More updates to come, good or bad.

 

[bart_dood]

Here's the additional work that I did on this repair. I believe that Phase A had a small leak on these clamshell pieces, at the corner. There is a plastic cover that goes over the end that bolts onto the gearbox. You can see this is one of my previous post (it shows the 3 copper AC leads out of the inverter). This cover had coolant on it near Phase A on this removal, and also had a little coolant on another part of this cover. Which leads me to believe...either the sealing surface with the o-ring, that I added sealant around leaked again or the clamshell pieces were leaking. Also, when I pried apart the clamshell, Phase A looked like the black sealant had coolant on it when I popped them open. Obviously this could have been part of the disassembly process, but Phase A looked different than B or C.

Hopefully this end up being the problem. But installed everything last night and the car is back running again.

More updates to come, good or bad.

Neat, really interesting to see and I'm sure more folks will find this useful in the future as the cars age

 

[Jashev]

Apparently they don't know their own warranties:

The OP noted that it was a salvage vehicle. Even though it was recertified by Tesla for service, I still believe that voids all warranties.

 

[MP3Mike]

The OP noted that it was a salvage vehicle. Even though it was recertified by Tesla for service, I still believe that voids all warranties.

That shouldn't make any difference, the car being salvage shouldn't mean that they don't warranty the replacement parts that you pay them to install.

 

[Jashev]

That shouldn't make any difference, the car being salvage shouldn't mean that they don't warranty the replacement parts that you pay them to install.

They said they would warranty the replaced drive unit for a year. That is typical for an out of warranty replacement.

 

[MP3Mike]

They said they would warranty the replaced drive unit for a year. That is typical for an out of warranty replacement.

And their warranty page says "The Tesla Parts, Body & Paint Repair Limited Warranty begins on the purchase date of the part(s), and coverage extends for a period of 12 months. Specific categories of parts have unique warranty coverage periods: Drive Unit: 4 years or 50,000 miles, whichever comes first".

Like I said, they don't even know their own warranty policies.

 

[stang_shane]

And their warranty page says "The Tesla Parts, Body & Paint Repair Limited Warranty begins on the purchase date of the part(s), and coverage extends for a period of 12 months. Specific categories of parts have unique warranty coverage periods: Drive Unit: 4 years or 50,000 miles, whichever comes first".

Like I said, they don't even know their own warranty policies.

I would have to agree. Still a new car company and there is a lot of information out there and yet a lot of misinformation out there. I've seen plenty of stories of salvage cars getting "warranty" work but I wasn't as lucky. So, I take the route I take with everything else. Dont depend on someone else and just take it apart.

I would say Phil or Ingineerix is awesome. I'm amazed at how much he knows on this car. I needed his help with diagnostics on both the initial error and follow up errors. I wasn't sure if I should mention him in case he wanted to stay somewhat anonymous so Tesla doesn't try to stop what he's doing, but after watching Rich's video today, he deserves so much more credit. Like he mentions, he supports over 600 cars that Tesla gave up on, just like mine.

 

[rooter]

Well I was going to congratulate you on your ingenuity... but then you mentioned Phil. He has a reputation for unpleasantness to alot of ppl.

 

[stang_shane]

Thanks for the almost congratulations.....I guess....even though your follow up insinuation that what I'm doing isn't my own "ingenuity", it's more of an insult. Perhaps other owners have had this same DU issue, done the same amount of work that I've done, taking an inverter completely apart, sealed it back up and reinstalled...although I've yet to find the level of detail that I've decided to share. My perception is that most Tesla owners at this point don't want to tear the car apart themselves, but that will change over time and this information will hopefully help someone that needs help.

I can't speak for other's interactions with Phil but for what he is doing in the big picture, I don't know anyone else that could have helped. I've owned tons of ICE cars and I've learned that the most valuable person to find is a tuner for the car. Tear apart an engine, upgrade, throw it back together, upgrade fuel system, change gears, add boost, etc and you need someone that changes the parameters of the car. Until you find a tuner or hacker, good luck accomplishing anything, especially considering I don't live in a right to repair state and I would never have access to determine what my error codes would have been on my Tesla. Perhaps there are other hackers that perform the same type of work, but Phil is the only one I found and he helped exactly as much as I think I needed.

Not sure if you've had your own issues with Phil or you just like to spread negativity based on what people write on forums.

 

[rooter]

You haven't been around long enough to know his history.

There are two groups, the commercial hackers, and the community hackers. The latter category are harder to find, but larger and cheaper. (Side note: I have no time to assist) Commercial hackers will never never give you root on your own car, and monitor your movements, actions, etc at their whim. Community hackers give you root on your own car, and if you are technically able, that is everything.

Not intending to impugn your abilities or motivation; both commendable and unusual. But I would have had a much higher opinion if you'd done it on your own like I did. I bought a front-ender, and a rear-ender, and put the good frontend on the front-ender... and got all the systems working again all before anyone had any technical information about these cars. Of course the rebuild took me 6 months full-time.

Then I was the first to sell the parts I didn't need (from the parts car) and made back $12k more than I had paid for both cars, and benefited alot of folks desperate for parts. Rich Benoit (RichRebuilds) asked and asked for my price list when he was starting out, and when I finally gave it to him he ended up competing with me!

Finally, I am the only one to ever publish a rooting method... which is irreversible by Tesla and always will be, of course having learned some from others as we all do but figuring out much on my own hard knocks, since almost none are forthcoming. I should also note that most others in the community know alot more than I do.

 

[stang_shane]

Follow-up:

The car seems to be fixed this time. Been a few weeks and no issues. I'm still assuming that the inverter cooling plate(s) were the issue since that's basically what I sealed up this time as compared to the previous "repair".

I'll be sure to update this thread is anything else comes up again related to the same problem.

 

[laurynas]

Follow-up:

The car seems to be fixed this time. Been a few weeks and no issues. I'm still assuming that the inverter cooling plate(s) were the issue since that's basically what I sealed up this time as compared to the previous "repair".

I'll be sure to update this thread is anything else comes up again related to the same problem.

Great thread @stang_shane . Thank you!
Any new issues with sealed plates yet? Just find out that I have the same problem. Thinking what to do. Fix or replace?