Model 3 rotor overheat

[Tadros]

Greetings all. I have a recurring rotor overheat issue I'd love your thoughts on.

June 2018 bought rwd long range model 3.

April 2020 rear motor fails and is replaced under warranty.

December 24, after 45 min of driving in 15F temp, rotor starts to overheat at highway speeds causing significant loss of drive power with speed decreasing from 75 setpoint down to around 60 on mild uphills despite accelerator pedal fully depressed. Similar situation occurred a week later.

Service determined motor coolant was overfilled from the factory at 2.5 L instead of 2.3L

Feb 3 2021, same issue. 10F, after driving 40 min with heater on, loss of acceleration / limitation of drive power, decrease in speed from 75 to 55 while going up a moderate hill. I assume this will be another rotor overheat.

Any idea what would be causing inadequate rotor cooling in very cold outdoor temperatures? Service appt scheduled for Feb 10.

 

[arnis]

"coolant overfill" can't do that.
I suspect problem with circulation. For example octovalve isn't working right or something more awesome,
for example, hoses are reversed. It is also possible that coolant pump reports it runs but actually it doesn't.

Last motor failed due to overheat? Well.. Tesla needs to fix software - overheat protection should actually PROTECT.

 

[ThomasD]

Ice forming in lines leading to pump cavitation

 

[Tadros]

Re: Thomas, yeah, I imagine that's it, it just seems odd that the coolant would do that. any idea what the composition of the rotor coolant is? If it's a glycol base like ice engines, one would think that the guys in Milwaukee doing the install would get the antifreeze mixture right. If it's oil-based, how would water be getting into that circuit?

Re: arnis, I'm not really sure how the previous motor failed. One morning I came out and the entire high voltage circuit wasn't engaging, had the car towed and they said that it was something in the motor. I didn't have any similar high temperature problems, so I think the prior motor failure was something different. I'll let you know what they find with the service.

 

[Tadros]

Word from Tesla Service is that an occlusion / ice in the coolant line would cause many additional alarms to pop up which didn't occur. However, 'oil' leaking from the motor would cause this picture. Motor was swapped out under warranty, will update if this doesn't resolve the issue. Thanks all!

 

[Tadros]

Well, we're still having the same issue: after driving ~45 minutes at highway speed NOT IN TRAFFIC, the drive power tapers off and the car slows down. This is fixed by engaging regen for a few seconds; the drive power rises back up and the car drives at highway speeds for a few minutes, then it repeats.

The other fix is that if you start going downhill, the drive power returns.

So far, none of the repair techniques used by Tesla have worked:

Coolant flush- failed
Motor replacement- failed
Superbottle replacement- failed
Rear body control module replacement- failed.

Here's what it looks like from the driver's perspective:

Car's been in the shop for about 24 hours, no word from the technicians so far on their 5th plan of action. You guys have any ideas?

 

[pcpro]

Well, we're still having the same issue: after driving ~45 minutes at highway speed NOT IN TRAFFIC, the drive power tapers off and the car slows down. This is fixed by engaging regen for a few seconds; the drive power rises back up and the car drives at highway speeds for a few minutes, then it repeats.

The other fix is that if you start going downhill, the drive power returns.

So far, none of the repair techniques used by Tesla have worked:

Coolant flush- failed
Motor replacement- failed
Superbottle replacement- failed
Rear body control module replacement- failed.

Here's what it looks like from the driver's perspective:

Car's been in the shop for about 24 hours, no word from the technicians so far on their 5th plan of action. You guys have any ideas?

Hey. My car is doing this. Got the drive unit replaced in January. I lose acceleration/torque driving down the highway. Now they’re telling me it’s a known issue that isn’t fixed yet but will be fixed by a future firmware update. What was your resolution if any?