2019 Tesla Model S Fluid Type Specifications & Capacities

Welcome to the comprehensive fluid specification guide for the 2019 Tesla Model S. As an ASE-certified master technician, I often hear from owners who assume that because their vehicle is entirely electric, it requires no fluid maintenance whatsoever. This is a dangerous misconception. While you won’t be changing engine oil or topping off diesel exhaust fluid, your Model S relies on a highly sophisticated thermal management system, high-speed gear reduction drive units, and a traditional hydraulic braking system—all of which require specific, high-quality fluids to operate safely and efficiently.

Whether you are driving a Long Range, Standard Range, or Performance model, using the exact factory-specified fluids is critical. Below is the complete fluid breakdown for your 2019 Tesla Model S.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil	N/A (Electric Vehicle)	N/A
Battery/Thermal Coolant	G48 HOAT (Ethylene Glycol, Blue/Green)	~3.5 - 5.0 Gallons (varies by battery pack)*
Front Drive Unit Fluid	Dexron VI Synthetic ATF	~1.5 - 1.8 Quarts*
Rear Drive Unit Fluid	Dexron VI Synthetic ATF	~1.5 - 2.3 Quarts*
Brake Fluid	DOT 4	~0.85 Quarts (0.8 Liters)
Power Steering Fluid	N/A (Electronic Power Assist Steering)	N/A
Windshield Washer Fluid	Standard / All-Season	3.2 - 4.5 Liters
DEF / Transfer Case	N/A	N/A

*Note: Capacities can vary slightly based on the specific drive unit iteration (e.g., Performance vs. Long Range) and battery pack size. Always verify exact fill levels using Tesla's Service Mode or OEM service info.

---

Battery and Drive Unit Coolant

Type: G48 HOAT (Hybrid Organic Acid Technology) Ethylene Glycol
Color: Blue / Green

Unlike a traditional internal combustion engine that uses coolant strictly to prevent overheating, the 2019 Tesla Model S uses its coolant to manage the temperature of the high-voltage battery pack, drive units (motors), and power electronics. It heats the battery in freezing weather for optimal charging and cools it during heavy acceleration or DC Fast Charging.

Common Pitfalls: Never mix OAT (Organic Acid Technology like Dex-Cool) with the factory HOAT (G48) fluid. Mixing these can cause chemical reactions that lead to sludge buildup, potentially blocking the microscopic cooling channels inside the battery pack. A battery pack replacement due to thermal management failure is a catastrophic expense. Also, do not use universal "all-makes, all-models" coolants. Stick strictly to G48 specification coolant mixed 50/50 with distilled water.

Intervals: Tesla's official maintenance schedule states that the battery coolant does not need to be replaced for the life of the vehicle under normal circumstances. However, if a thermal system component (like a pump, valve, or chiller) is replaced, the system must be vacuum-filled and bled using Tesla's diagnostic software.

Drive Unit Fluid (Transmission / Differential)

Type: Synthetic Dexron VI ATF (Automatic Transmission Fluid)

Electric vehicles don't have multi-gear transmissions, transfer cases, or traditional differentials that require heavy 75W-90 or 75W-140 gear oil. Instead, the 2019 Tesla Model S uses a single-speed gear reduction integrated with an open differential inside the drive unit. Because the electric motors spin at incredibly high RPMs (upwards of 18,000 RPM), Tesla specifies a lightweight, high-shear-stable fluid: Dexron VI Automatic Transmission Fluid.

Common Pitfalls: Do not use traditional gear oils (GL-4 or GL-5) in a Tesla drive unit. The high viscosity will cause excessive drag, ruining your vehicle's efficiency and range, and failing to properly lubricate the high-speed bearings. Stick to a high-quality, fully synthetic Dexron VI ATF.

Intervals: Tesla previously recommended drive unit fluid changes at 12,500 miles or 1 year for early Model S generations to remove break-in wear metals. For the 2019 model year, Tesla considers the drive unit fluid a "lifetime" fill under normal operating conditions. However, many EV specialists and master technicians recommend draining and filling the drive unit fluid every 50,000 miles. The fluid is relatively inexpensive, and removing metallic particles (caught by the internal magnetic filter and drain plug) can drastically extend the life of the drive unit bearings.

Brake Fluid

Type: DOT 4 Brake Fluid

The 2019 Tesla Model S utilizes a heavy-duty hydraulic braking system. Because of the aggressive regenerative braking programmed into the electric motors, you will rarely use the friction brakes during normal daily driving. As a result, brake pads and rotors on a Model S can easily last over 100,000 miles.

Common Pitfalls: Because the brake pads last so long, owners often forget about the brake fluid. DOT 4 brake fluid is highly hygroscopic, meaning it constantly absorbs moisture from the atmosphere. Even if you never press the brake pedal, the fluid is degrading. If the moisture content gets too high, the boiling point of the fluid drops drastically, and internal corrosion can ruin the expensive ABS module and brake calipers. Never downgrade to DOT 3 fluid, as it has a lower boiling point.

Intervals: Tesla officially recommends testing the brake fluid for moisture contamination every 2 years and replacing the fluid if the moisture content exceeds 2%. Personally, I advise doing a full brake fluid flush every 2 to 3 years regardless, especially if you live in a humid climate or experience harsh winters.

Windshield Washer Fluid

Type: Standard or De-icing Washer Fluid (depending on climate)

Since the Model S does not generate waste heat from an engine block, the hood and windshield area can remain quite cold during winter driving. It is crucial to use a washer fluid rated for sub-freezing temperatures if you live in a cold climate, as a frozen washer fluid reservoir or cracked lines can be a costly annoyance to repair underneath the "frunk" assembly. Ensure you do not use fluids containing bug-wash additives that leave a film, as this can sometimes interfere with the vehicle's forward-facing Autopilot cameras mounted behind the windshield.

Missing Fluids: The EV Advantage

To reiterate, since the 2019 Tesla Model S is a Battery Electric Vehicle (BEV), you are permanently free from several routine fluid services:

• Engine Oil: No internal combustion engine, no API SP or dexos1 Gen3 oil needed.
• Power Steering Fluid: The Model S uses an Electronic Power Assist Steering (EPAS) rack, utilizing an electric motor rather than hydraulic fluid.
• Transfer Case / Traditional Differential Fluid: Handled entirely by the individual front and rear drive units using Dexron VI.
• Diesel Exhaust Fluid (DEF): No emissions systems, no ISO 22241 fluid required.

Conclusion

Maintaining a 2019 Tesla Model S requires a different mindset than traditional internal combustion vehicles, but it is no less important. Keeping the thermal management system sealed with the correct G48 HOAT coolant, ensuring the drive units have fresh Dexron VI ATF, and keeping moisture out of the DOT 4 brake system will keep your Model S performing flawlessly for years to come.

If you lack the specialized software to bleed the thermal coolant loops or prefer to leave high-voltage vehicle maintenance to the professionals, don't leave it to chance. Find a trusted shop on Repairius.