To all Tesla owners considering an LDU repair, please read this carefully before you make a decision that you cannot reverse. They want to censor EV Clinic.

This is not theory we are pushing it is something we confirm in practice, on every bench, in every workshop, every week.

There’s a lot of noise in the EV community right now about “coolant delete” being a cheap, easy, permanent fix for the leaking rotor seal on the first-generation Large Drive Unit, instead of a proper HolyGrail EVC remanufacturing. I want to talk to you directly, owner to specialist, because this decision has consequences that go far beyond what most people are telling you.

Let me start with something nobody else in this space is willing to do: we offer a 2-year, unlimited-mileage warranty on every LDU we remanufacture. Not 12 months. Not “up to 50,000 km.” Two full years, no mileage cap, on every single unit that leaves our facility. You don’t offer that kind of warranty on a workaround. You offer it when you’ve actually solved the problem, validated it on the bench, validated it on the road, and you know what’s coming back and what isn’t.

So why am I willing to put my company behind that warranty while coolant-delete shops won’t? Because the physics of what they’re doing doesn’t hold up under real-world load.

What a “coolant delete” actually does to your motor

The Tesla LDU was engineered as a single, balanced hydraulic cooling circuit. Coolant flows through the stator jacket, through a cover pipe that cools the rotor from inside the shaft, and back out. It’s one system, designed with specific pressure distribution, specific flow rates, and specific thermal balance assumptions baked into every component the inverter cold plate, the stator jacket, the bearing seats, everything.

When somebody “deletes” the rotor cooling branch, they are not removing a problem. They are introducing a new one. The hydraulic circuit becomes unbalanced. Pressure distribution shifts. Flow rates change. And in many cases, the inverter and stator actually run hotter after the delete than they did before, because the system was never designed to operate that way.

Now add the rotor to the equation. An induction rotor isn’t a passive component. It generates significant losses copper losses in the rotor bars, iron losses in the laminations, windage, friction. In normal operation, a meaningful portion of that heat is carried away by coolant flowing through the shaft. Delete that path, and the heat has nowhere to escape except into the air gap, where it radiates directly into the stator end-windings the most vulnerable part of the entire motor. Those end-windings have no active cooling. They sit exposed in the center of the stator, surrounded by air that is now significantly hotter than it should be.

What we see, repeatedly, on coolant-delete motors that come into our workshops:

• Insulation darkening and embrittlement on the end-windings
• Micro-cracks forming in the varnish layer
• Discoloration on the bearing races from heat soak through the rotor shaft
• Premature grease degradation in the bearings
• Inverter IGBT/SiC modules showing thermal stress
• The rotor oil seal on the gearbox side burning and cracking under sustained heat — releasing gearbox oil into the stator cavity and leaving the gearbox running dry. Both motor and gearbox destroyed in a single failure event.
• Eventually: stator insulation collapse, often without any coolant intrusion at all

That last point is the part that exposes the entire coolant-delete argument as a logical contradiction.

The whole reason coolant delete was invented was to “save the stator from coolant ingress.” That was the entire justification. The proposed solution: remove the coolant from the rotor, no more coolant near the stator, problem solved. Simple, intuitive, and completely wrong in practice.

Because here is what we actually see on coolant-delete motors arriving with destroyed stators: there is no coolant inside them. The stator is dry. The rotor cavity is dry. There has been no ingress at all. And yet the windings are burned, the insulation has collapsed, and the motor is finished. The thing that was supposed to be the fix is now the cause. The delete didn’t save the stator from coolant it killed it with heat. Same victim, different murder weapon, dressed up as a rescue.

Why the driver never sees it coming the stator temperature blind spot

Here is something almost nobody discusses, and it should worry every coolant-delete driver.

The Tesla LDU has only one stator temperature sensor, mounted on the stator iron core not on the end-windings, not in the air gap, not on the rotor. That iron core is still being cooled by the stator jacket after a delete, so the dashboard, the logs, every diagnostic readout shows stator temperature normal.

Meanwhile, the actual damage is happening in a place the sensor cannot see. The end-windings cook. The varnish darkens. The insulation embrittles. The sensor keeps reporting a comfortable number, because the iron it’s bolted to is still cool. By the time an error code finally fires, a winding has shorted and the unit is destroyed.

This is why coolant-delete advocates can honestly say “my temperature never spiked.” Of course it didn’t. The thing burning is not the thing being measured. Real engineering does not rely on a sensor that cannot see the damage.

How fast does it actually fail?

This isn’t a slow, gentle decline. We’ve seen motors fail at around 20,000 km after a coolant delete in warm climates with aggressive driving sometimes earlier. Units arriving from Slovakia, Slovenia, Austria destroyed shortly after a coolant-delete “repair.” Colleagues across the industry who push this method are increasingly forced to install replacement LDUs to customers at their own cost.

Why “Tesla does it now” is misleading

You’ll hear: “Tesla themselves delete the rotor coolant pathway in the Revision U, so it must be fine.”

The truth: the Tesla LDU has been on the market for thirteen years, and Tesla has revised the cooling and sealing arrangement more than a dozen times. Every revision is a tacit admission that the previous one didn’t work. Each new letter is Tesla quietly fixing what they got wrong, without ever publicly acknowledging the original engineering mistake. Remember when the S85 narrative was “the LDU never fails”?

Revision U is not a solution. It is the thirteenth attempt at fixing a problem that should never have existed. It may run cooler in mild conditions and short trips. But Central Europe, Southern Europe, the American Southwest sustained highway speeds and high ambient temperatures expose the same fundamental weakness. The U-revision stator is new, so degradation will take time, but the same failure mode is coming. An induction motor without an internal heat extraction path will thermally saturate under load. That’s not opinion. That’s basic motor design.

The Toyota RAV4 EV and Mercedes B250e use the same Tesla-supplied LDU and have identical coolant ingress and thermal failure issues. This isn’t a Tesla manufacturing defect. It is a fundamental design choice that was wrong from day one and has been getting band-aids for over a decade.

The “they just want to sell you a fancy seal” accusation

I want to address this head-on because it’s not just wrong- it’s backwards.

The graphite mechanical face seal we use was not pulled out of a generic catalog. It is a sealing technology engineered for industrial abuse far beyond anything an LDU will ever see in a car:

• Pressure rating up to 20 bar of sustained operating pressure the LDU coolant circuit runs at a tiny fraction of that
• Full chemical resistance to coolant, gearbox oil, condensation does not swell, harden, or chemically degrade like rubber lip seals
• Self-healing sealing face minor surface imperfections are polished out by the seal’s own running action, the opposite of how a lip seal behaves
• Temperature capability up to ~400°C conditions a motor cannot physically survive
• Roughly 10× lower friction than PTFE does not grind the rotor shaft, does not generate parasitic heat, does not consume itself

That is what is being dismissed as a “fancy seal” by people whose alternative is to cut a coolant pipe with an angle grinder. One is engineering. The other is amputation.

Beyond the seal, the accusation also misses the bigger commercial logic. If our business model were to maximize repeat customers, coolant delete would be the most profitable thing we could possibly offer. A coolant-delete motor comes back at 20,000 km, at 50,000 km, at 130,000 km with rotor shaft micro-cracking. Every return is another invoice.

We do the opposite. We rebuild the LDU to last one million kilometers without service ; and we have road validation data to prove it. Units approaching 800,000 km on our HolyGrail e-Drive kit with zero overheating, zero coolant intrusion, zero stator failures, zero gearbox oil seal failures. Documented, on the road, in customer cars, right now.

Our process is a complete engineering remanufacturing: full bearing replacement, complete seal and o-ring replacement throughout the unit including the gearbox-side oil seal, rotor shaft machining to restore the sealing surface, installation of the graphite mechanical face seal, bench validation with our EVC Explorer before the unit goes back in a car, correct adhesives, correct torque, correct procedure end to end.

That is why we offer 2 years and unlimited mileage. Not optimism. Validation.

On the rotor shaft “evidence”

You’ll see photos shared of a rotor shaft with a micro-crack at 280,000 km, used to argue that “no seal works, so coolant delete is the only option.”

That photo is evidence of the opposite conclusion. The crack is caused by the standard lip seal grinding against the shaft for hundreds of thousands of kilometers. The solution is not to remove cooling the solution is to stop using a sealing technology that destroys the shaft. A properly machined shaft surface plus a graphite mechanical seal eliminates the grinding contact almost entirely. The wear mechanism that caused the original failure is engineered out of the system.

What it actually costs you

Coolant delete is sold as the “cheap” option. The real numbers tell a different story.

If the motor survives, you’ve saved 800–1,500 euro versus a proper reman today. If it fails, the cost of fixing it properly goes up, not down:

• The internal coolant cover pipe is often damaged or removed during the delete. Tesla does not sell that part. Only source: cannibalizing another LDU. Roughly +€800.
• The rotor shaft is often shortened during the delete new rotor or major machining required.
• An overheated stator means a new stator on top of everything else roughly €1,800 + VAT.
• A destroyed gearbox from oil seal failure means rebuilding two assemblies instead of one.

A normal EVC reman that would have cost ~€2,800 becomes €3,600 + stator + VAT, easily €5,500–€6,000 and significantly more if the gearbox went with it. Do it once, do it right is not a slogan. It is arithmetic.

Why would you pay €1,500 for a coolant delete and make e-mobility less sustainable, when the same money is the down-payment on a repair that destroys the car?

One more thing ; and this one is personal

I have to address something that has been quietly poisoning this conversation for years.

There is a network of self-appointed “non-professionals” on Facebook coolant-delete shop owners, moderators of the largest Tesla owner groups, well-known names in the US scene like Ray J. and his close circle who have spent years pushing one convenient narrative: that coolant delete is fine, that it’s the only sane option, that anyone who disagrees is “trying to sell you something.” That narrative did not survive on its merits. It survived because the people pushing it actively suppress every voice that contradicts it.

EV Clinic has been censored in these groups for years. Posts removed. Comments deleted. Warnings to owners buried before they could be read. Technical explanations from a facility that sees more LDU failures in a single week than some of these “moderators” see in a year gone, because they didn’t fit the storyline. Owners asking honest questions get steered away from real answers. Long-time members get muted for raising the same concerns we are raising right now.

And let me be clear: this censorship is not limited to LDU and coolant delete. The same pattern repeats whenever we publish information that contradicts whichever home-shop solution is being promoted at the time. BMS faults like F107, F123, U029, U025. Battery pack issues. HV contactor problems. Drive unit DI_F072. Charging port and OBC failures. HVIL diagnostics. Across the entire Tesla platform, every time we share a real engineering explanation that exposes a shortcut, a band-aid, or a misdiagnosis being sold as a fix the post gets removed, the comment gets deleted, the warning gets buried before owners can read it. This is not coincidence. It is a system. And EV Clinic has been on the receiving end of that censorship longer than almost anyone else in this space, because we publish the technical truth even when it is commercially inconvenient for the people running the room.

This is not a debate on a level playing field. It is a curated narrative, maintained by people who benefit directly from keeping their preferred “solutions” coolant delete, $2 caps, dubious BMS resets, mystery battery fixes looking like the obvious choice. Customers, favors, free Tesla service in exchange for staying quiet on the real problems, social capital as the loudest voices in the room. The incentive is the same: keep the narrative simple, keep the alternatives invisible, keep the owners in the dark.

I’m done being polite about it. Tesla owners deserve better than censorship.

First adopters in particular the people who bought a Roadster in 2009, a Model S in 2012, who put their money behind electric mobility before it was safe or popular or fashionable to do so those people built this industry. They took the risk. They paid the early-adopter tax. They believed in something the rest of the world was still laughing at. And what are they being offered now, more than a decade later, when their drive units, their battery packs, their BMS modules finally need attention? A cut pipe, a cheap reset, and a shrug.

That is not a solution worthy of the people who made Tesla what it is.

First adopters deserve transparency. Real engineering, not a workaround dressed up as innovation. The truth about what is in their car, what has been done to it, and what is going to happen to it in 20,000 or 50,000 or 130,000 km. A repair that lasts a million kilometers, not one that lasts until the next heatwave or the next mountain pass. A warranty that means something written, signed, with real duration and real mileage behind it. They deserve to be talked to like the technically literate, mechanically curious, future-oriented people they are not managed like an audience that needs to be steered toward whatever option keeps the loudest voices comfortable.

We have been EV enthusiasts since the very first Tesla Roadster. We didn’t arrive in this industry to sell coolant deletes, and we did not build EV Clinic to be quiet while owners get misled across every Tesla subsystem there is. We arrived because we believed and still believe – that the people who took the leap on electric mobility before anyone else are owed a level of honesty and durability that matches the leap they took. A million kilometers without overhaul. A real warranty. A real engineering process. A real seal designed for industrial abuse. Real BMS diagnostics, real battery analysis, real answers not a reset, a hope, and a deleted comment when somebody asks a follow-up question.

That is the standard. That is what this community deserves. And no amount of Facebook moderation, comment deletion, group bans, or coordinated narrative-pushing by Ray J. or anyone else who has built their position on silencing inconvenient voices is going to make EV Clinic stop saying it.

What I’m asking you to do

Three things.

First, ask any shop offering a coolant delete what warranty they put on it duration in writing, mileage cap in writing, what happens if your stator burns at 30,000 km or your gearbox runs dry from a cooked oil seal. Almost nobody offers what we offer, because almost nobody can stand behind that work for that long.

Second, if you’re buying a used Model S or X, ask the seller specifically what has been done to the drive unit. A coolant delete history affects the value of the car and the cost of any future proper repair. You have a right to know.

Third, ignore the noise from people whose entire experience is two motors a month in mild climates with gentle drivers and especially ignore the people who silence anyone presenting a different view. Look at the volume data. Look at the failure cases. Look at the engineering. Look at who is willing to put their name and their warranty on the line, and who is hiding behind moderator privileges and group rules.

The LDU was a flawed design from 2012. Thirteen revisions later, Tesla still hasn’t made it right. We have. And we’re willing to put a 2-year unlimited-mileage warranty behind that statement, every single time, in writing, no exceptions.

Drive safe. Make informed decisions. And if you want a real solution rather than a workaround, you know where to find us.

EVC Research & Development / backed by 20 EVC engineers Zagreb · Ljubljana · Berlin · Belgrade · Budapest · Paris Soon: Romania · Istanbul

“Coolant delete” is not destroying just LDU, even all other INDUCTION Edrives”

Affected Vehicle 2013-2022 Model S and X:
RWD
S85
S60
S70
S75
S90
P85
P90

4×4
P85D
P90D
P100D

How to properly do LDU HolyGrail Reman:

THIS IS EXAMPLE HOW COOLANT DELETE FAILS.