2018 Tesla Model 3 Fluid Type Specs & Capacities

As an ASE-certified master technician, I’ve seen the automotive industry rapidly shift toward electrification. While the 2018 Tesla Model 3 eliminates the traditional internal combustion engine (ICE), it still relies on highly specialized fluids to keep its sophisticated thermal management system, drive units, and braking systems operating at peak efficiency.

Because electric vehicles (EVs) have entirely different heat generation characteristics and mechanical layouts than gas-powered cars, using the wrong fluid can lead to catastrophic battery or drive motor failures. In this comprehensive guide for Repairius.com, we will break down exactly what goes into your 2018 Tesla Model 3, factory-specification numbers, and common pitfalls to avoid.

Quick reference

Note: Capacities can vary slightly depending on whether your Model 3 is Standard Range (RWD), Long Range (RWD/AWD), or Performance (AWD). Always verify exact amounts with Tesla service information.

Fluid	Type/Spec	Capacity
Engine Oil	N/A (Electric Vehicle)	N/A
Drive Unit / Gear Fluid	Dexron VI ATF (Tesla Spec: 1031156-00-A)	~1.25 L (per drive unit)
Battery & Motor Coolant	Ethylene Glycol HOAT (G48) / Tesla HT-12	~8.0 - 9.0 L (Total System)
Brake Fluid	DOT 4 (Tesla Spec: 1047661-00-A)	~0.8 L
Power Steering Fluid	N/A (Electronic Power Steering)	N/A
Washer Fluid	Standard Washer Fluid	~3.2 L (1 Gallon)
DEF / Diesel Exhaust	N/A	N/A

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Drive Unit / Gearbox Fluid (Transmission)

Unlike a traditional automatic transmission, the Tesla Model 3 utilizes a single-speed gear reduction unit integrated with the electric motor and differential. Despite its simplicity, this high-speed gearbox requires excellent lubrication and cooling properties.

The Spec: Tesla specifies a high-quality automatic transmission fluid (ATF) for the drive units. The factory fill is essentially a Dexron VI equivalent. Tesla’s OEM part number is often listed as 1031156-00-A (Pentosin ATF 9 is a common OEM supplier equivalent). Capacity: Approximately 1.25 Liters per motor. Dual Motor (AWD) vehicles will have a front and rear drive unit, each requiring fluid.

Intervals & Pitfalls: Tesla famously stated early on that the drive unit fluid was a "lifetime" fill. However, as master technicians, we know that no fluid lasts forever, especially given the immense torque loads these gearboxes endure. Best practice among EV specialists is to inspect or replace this fluid around the 50,000-mile mark. Pitfall: Never use heavy gear oils (like 75W-90) in these drive units! The tight tolerances and high RPMs of the electric motor require the thin viscosity of an ATF like Dexron VI. Using traditional gear oil will cause severe drag, overheating, and potential bearing failure.

Battery and Thermal Management Coolant

The lifeblood of the 2018 Tesla Model 3 is its active thermal management system. The vehicle uses a single, interconnected liquid cooling loop to manage the temperature of the high-voltage battery pack, the drive units, and the power electronics.

The Spec: Tesla uses a specific Hybrid Organic Acid Technology (HOAT) coolant. The factory fluid is typically a G48 formulation (often blue/green) or the newer Tesla HT-12. The mixture must be a 50/50 blend of coolant and de-ionized water. Capacity: The entire system holds approximately 8.0 to 9.0 liters, depending on the battery size and AWD/RWD configuration.

Intervals & Pitfalls: Tesla recommends checking the battery coolant level periodically. Replacement is generally recommended every 4 to 5 years, depending on your climate and charging habits. Pitfall: Never mix OAT coolants (like Dex-Cool) with the Tesla HOAT fluid. Mixing incompatible coolants can cause gelling, which will clog the micro-channels in the battery pack cooling ribbon. If the battery cannot cool itself, the vehicle will enter a reduced-power mode and potentially cause irreversible battery degradation. Furthermore, never use standard tap water; the system requires a specific dielectric resistance to prevent high-voltage shorts, meaning only pre-mixed EV-rated coolants or de-ionized water should be used.

Brake Fluid

Even though the Model 3 heavily relies on regenerative braking (using the electric motors to slow the vehicle down), the friction brakes are still crucial for hard stops, emergencies, and holding the vehicle on steep inclines.

The Spec: Tesla strictly specifies DOT 4 brake fluid (Tesla part number 1047661-00-A). Capacity: Approximately 0.8 Liters to flush the system.

Intervals & Pitfalls: Because regenerative braking does most of the daily work, the physical brake pads and rotors on a Model 3 can last a very long time. However, this causes a hidden issue: brake fluid is hygroscopic, meaning it absorbs moisture from the air over time, regardless of how often you use the brakes. Tesla recommends testing the brake fluid for moisture every 2 years and flushing it if necessary. Pitfall: Do not downgrade to DOT 3 fluid. DOT 4 has a higher boiling point, which is necessary for a heavy vehicle like the Model 3 when the friction brakes are called upon. Never use DOT 5 (silicone-based) fluid, as it is completely incompatible with the Model 3's ABS and stability control system.

Washer Fluid

The Spec: Any high-quality automotive windshield washer fluid. Capacity: Roughly 3.2 Liters (just under a US gallon).

Intervals & Pitfalls: Top off as needed. In freezing climates, ensure you are using a winter-grade washer fluid rated for below-freezing temperatures. Using summer bug wash in the winter can cause the reservoir and lines to freeze and crack.

Fluids Not Applicable to the Model 3

As an EV, the 2018 Tesla Model 3 does not have an internal combustion engine, meaning several traditional fluids are entirely absent from the maintenance schedule:

• Engine Oil: No API SP, GM dexos1 Gen3, or Ford WSS-M2C946-B1 to worry about.
• Power Steering Fluid: The Model 3 uses an Electronic Power Assist Steering (EPAS) rack, consisting of an electric motor and a belt/gear drive. There are no hydraulic pumps, lines, or fluids to leak.
• Transfer Case / Differential Fluid: The front and rear differentials are integrated into the drive units and share the Dexron VI ATF mentioned above.
• Diesel Exhaust Fluid (DEF): Obviously, no API CK-4 / ISO 22241 applies here.

Electric vehicles might have fewer fluids than their internal combustion counterparts, but the fluids they do use are absolutely critical to vehicle longevity and safety. Always ensure you or your technician are using the precise factory specifications.

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