Tesla Large Drive Unit LDU Coolant Delete
Philip Defatta • February 11, 2026
Coolant intrusion - Rust in stator windings - LDU
The rear drive unit in older Teslas model X and S have a costly design problem. Many Tesla Model S and Model X vehicles made from 2012 to 2020 have the Large Drive Unit (LDU), which has a guaranteed leaking rotor coolant seal. This seal, located around the electric motor rotor shaft, will fail and allow coolant to seep into the motor. Over time, every one of these will leak. Tesla tried various fixes to prevent this, then introduced ‘Revision U’ of the LDU in late 2022. This versionor reroutes coolant away from the rotor while continuing to cooling the inverter, stator, and gearbox through the flyover tube. This is a good and permanent fix.
This issue impacts ALL rear-wheel-drive models (including non-performance RWD ones) and all Performance (P-series) dual-motor variants. The non-performance dual-motor models use a different rear unit without this flaw. While Performance and non-performance LDUs differ in their inverters, they share the same leaky seal. Only the NON-PERFORMANCE DUAL-MOTOR vehicles have the ‘small drive unit’ that’s immune to this. Newer Model 3/Y and the latest S/X do not leak coolant into the stator.
If you own an impacted vehicle, make it a habit to inspect the encoder (or speed) sensor for signs of blue coolant buildup. It’s a straightforward inspection. If yours is leaking, act quickly to get it fixed before the motor floods and the car becomes undrivable. We perform this inspection for $49.
Pre Revision U LDU’s can be modified to have the Revision U fix. This is known as the coolant delete. In fact it does not eliminate cooling for the whole Large Drive Unit, it only by passes the rotor cooling. Contact Philip at PROFIX Auto Repair for details and pricing. Don’t delay getting your LDU checked for $49.
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