2015 Tesla Model S — Complete Fluid Type Specifications

As an ASE-certified master technician, transitioning from traditional internal combustion engines (ICE) to electric vehicles (EVs) requires a significant shift in how we approach preventative maintenance. The 2015 Tesla Model S is a prime example. While you won't be dealing with 5W-30 motor oil, multi-gear transmission fluid, transfer case gear oil, power steering fluid, or Diesel Exhaust Fluid (DEF), this performance EV still relies heavily on specific fluids to manage temperatures, lubricate reduction gears, and stop a very heavy vehicle safely.

Below is the complete, factory-spec fluid guide for the 2015 Tesla Model S, covering both rear-wheel drive (RWD) and dual-motor all-wheel drive (AWD) "D" configurations.

Quick reference

Fluid	Type/Spec	Capacity
Drive Unit / Gear Oil	Dexron VI ATF (OEM Spec)	RWD (Large Motor): ~1.5 Liters (1.6 Quarts)<br>Dual Motor Front: ~1.4 Liters (1.5 Quarts)
Thermal Management Coolant	Ethylene Glycol HOAT (Zerex G48 / BASF Glysantin G48), Blue-Green	~3.5 - 4.5 Gallons (Depends on battery pack & AWD configuration. Verify in service info)
Brake Fluid	DOT 4 Brake Fluid	~1.0 Liter (1.05 Quarts)
Windshield Washer Fluid	Standard Automotive Washer Fluid	~4.0 Liters (1 Gallon)
A/C Refrigerant	R134a (Check underhood label)	~750 grams (Verify exact charge on underhood label)
A/C Compressor Oil	POE Oil (ND-Oil 11) for electric compressors	~120 ml
Engine Oil	N/A	N/A
Power Steering	N/A (Electronic Power Steering)	N/A

Note: Capacities are approximate dry-fill numbers. Always verify levels at the fill plug or reservoir cold-fill lines per OEM service information.

Drive Unit / Gear Fluid

Even though the Tesla Model S doesn't have a traditional multi-speed transmission or differential, it does utilize a single-speed reduction gear set inside the drive unit(s). To keep these high-speed gears lubricated and cool, Tesla specifies Dexron VI Automatic Transmission Fluid (ATF).

• RWD Models: Feature a single large drive unit in the rear requiring approximately 1.5 Liters.
• Dual Motor (AWD) Models: Have both front and rear drive units. The front drive unit typically takes about 1.4 Liters, while the rear takes 1.5 Liters.
• Maintenance Notes: Tesla originally stated the drive unit fluid was a "lifetime" fluid. However, many master technicians and EV specialists recommend replacing the drive unit fluid every 50,000 to 60,000 miles to remove metallic wear particles and ensure the longevity of the reduction gears and bearings. Always clean the magnetic drain plug thoroughly before reinstalling. Never use heavy gear oils (like 75W-90) in these drive units; the tight clearances require the low viscosity of Dexron VI.

Thermal Management Coolant (Battery & Drive Unit)

Heat is the enemy of lithium-ion batteries and high-output electric motors. The 2015 Tesla Model S uses a complex thermal management system that loops coolant through the battery pack, drive unit(s), and power electronics.

• Specification: The required coolant is a Hybrid Organic Acid Technology (HOAT) based on ethylene glycol. Specifically, Tesla uses G48 coolant (commonly available as Zerex G48 or BASF Glysantin G48), which is blue-green in color.
• Maintenance Notes: Tesla originally recommended replacing the battery coolant every 4 years or 50,000 miles. They have since updated their maintenance schedules to say the coolant only needs to be checked and replaced as needed. However, testing the coolant's pH and freezing point every few years is highly recommended to prevent internal corrosion of the battery's cooling ribbons.
• Common Pitfalls: NEVER mix OAT (Organic Acid Technology like Dex-Cool) with HOAT (G48). Mixing incompatible coolant types can cause the corrosion inhibitors to drop out of suspension, creating a gel-like sludge that will block the highly restrictive micro-channels inside the battery cooling system. A restricted battery cooling system will severely limit charging speeds and vehicle power, and could result in catastrophic battery failure. Furthermore, always use a vacuum-fill tool when replacing this coolant; the complex routing of hoses makes it virtually impossible to bleed air pockets manually.

Brake Fluid

Because EVs rely heavily on regenerative braking to slow the vehicle, the friction brakes on a 2015 Model S often see far less use than those on a traditional gas-powered car.

• Specification: High-quality DOT 4 Brake Fluid.
• Maintenance Notes: Tesla recommends testing brake fluid health every 2 years and replacing it if the moisture content exceeds 3%. Because the brake pads are used so infrequently, moisture buildup in the fluid is actually a primary concern. The lack of heat cycling means water that naturally absorbs into the hygroscopic DOT 4 fluid isn't boiled off. This can lead to internal corrosion of the brake calipers and ABS modulator. Flushing the system every 2 to 3 years is cheap insurance.

Windshield Washer Fluid

Nothing overly complicated here. The Model S uses standard automotive windshield washer fluid.

• Maintenance Notes: If you live in a cold climate, ensure you are using a winter-grade washer fluid rated for sub-zero temperatures to prevent the reservoir and lines from cracking.

A/C Refrigerant and Compressor Oil

The air conditioning system on a 2015 Model S isn't just for passenger comfort; it is a critical component of the battery thermal management system, acting as a chiller for the coolant loop during Supercharging and high-demand driving.

• Specification: 2015 models generally use R134a refrigerant.
• Compressor Oil Pitfall: The Model S uses a high-voltage electric A/C compressor. You MUST use POE (Polyolester) oil (specifically ND-Oil 11 or equivalent). Never inject standard PAG oil into an EV A/C system. PAG oil conducts electricity. Introducing PAG oil into a high-voltage A/C compressor can cause high-voltage leakage to the chassis, triggering a hard fault that will completely shut down the vehicle and destroy the compressor.

Maintain Your EV Safely

Servicing an electric vehicle like the 2015 Tesla Model S requires specialized knowledge, especially when it comes to bleeding the thermal management system or working around high-voltage components.

Find a trusted shop on Repairius.