2018 Tesla Model S Fluid Type Specifications

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil	N/A	N/A
Engine Coolant	Glycol-based, Tesla-approved	~16.5-17.5L
Transmission Fluid	N/A (single-speed direct drive)	N/A
Differential Fluid	Refer to service manual	~0.7-1.0L (each)
Brake Fluid	DOT 4	~1.0L
Power Steering	Electric (N/A)	N/A
Washer Fluid	Standard Washer Fluid	~4.5L
DEF	N/A	N/A

Engine Oil

The 2018 Tesla Model S is a fully electric vehicle and as such, does not require engine oil. The electric motors are sealed units and do not utilize traditional fossil fuel lubricants.

Engine Coolant

Tesla vehicles, including the 2018 Model S, utilize a liquid cooling system for the battery pack, power electronics, and electric motors. The coolant is a specific glycol-based formula approved by Tesla. It is crucial to use only Tesla-approved coolant to ensure compatibility with the system's materials and to maintain optimal thermal management. Using aftermarket or incompatible coolants can lead to corrosion, reduced cooling efficiency, and potential damage to critical components. Tesla does not typically provide a public-facing manufacturer spec number for their coolant, emphasizing the use of their official product.

Coolant capacity for the 2018 Model S is approximately 16.5 to 17.5 liters. Coolant should be checked and maintained according to the manufacturer's recommended service intervals, typically every 4 years or 50,000 miles, whichever comes first. Always verify the exact interval in your owner's manual or OEM service information.

Common Pitfalls: Never mix different types of coolants, especially not silicate-based with OAT (Organic Acid Technology) or HOAT (Hybrid Organic Acid Technology) coolants, as this can lead to gel formation and severe system blockages. Always use the specified Tesla coolant.

Transmission Fluid

The 2018 Tesla Model S utilizes a single-speed direct drive transmission for its electric motors. This design does not require traditional transmission fluid as found in multi-gear internal combustion engine transmissions. The drive unit, however, does contain a lubricant, but it is not a user-serviceable item and typically falls under differential fluid specifications.

Differential Fluid

Both the front and rear drive units of the 2018 Tesla Model S contain a lubricant similar to a differential fluid. While not a traditional "differential" in the ICE sense, these units house gears that require lubrication. Tesla specifies a unique lubricant for these drive units. It is essential to refer to the official Tesla service manual or an authorized Tesla service center for the exact specification and type of fluid required. Attempting to use generic gear oil could lead to premature wear or damage to the drive unit components.

The capacity for each drive unit is approximately 0.7 to 1.0 liters. Differential fluid is generally considered a "lifetime" fill by Tesla, meaning it's not typically part of routine maintenance unless there's a repair involving the drive unit. However, some owners choose to have it inspected or changed after higher mileage, especially if the vehicle is driven under demanding conditions. Always consult the owner's manual or official Tesla service information for recommended inspection and service intervals.

Brake Fluid

The 2018 Tesla Model S requires DOT 4 brake fluid. This is a common standard for modern vehicles due to its higher boiling point compared to DOT 3, which is important for maintaining braking performance under heavy use.

The approximate capacity for the brake fluid reservoir is around 1.0 liter. Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. This moisture contaminates the fluid, lowering its boiling point and potentially leading to a spongy pedal feel or reduced braking effectiveness. Tesla recommends inspecting and replacing the brake fluid every 2 years, regardless of mileage. Always verify the exact interval in your owner's manual or OEM service information.

Common Pitfalls: Never use DOT 5 (silicone-based) brake fluid in a system designed for DOT 3, 4, or 5.1. DOT 5 is not compatible and can cause severe damage to the braking system seals and components. Ensure you use fresh, sealed DOT 4 fluid to prevent contamination.

Power Steering Fluid

The 2018 Tesla Model S utilizes an electric power steering system. This system does not use hydraulic fluid like traditional power steering setups. Therefore, there is no power steering fluid to check or replace.

Washer Fluid

The 2018 Tesla Model S uses standard windshield washer fluid. Any commercially available quality washer fluid that offers freeze protection appropriate for your climate is suitable. Most washer fluids are a mixture of water, alcohol, and detergents.

The washer fluid reservoir typically holds approximately 4.5 liters. Check the level regularly and refill as needed. It's advisable to use a fluid with de-icing properties in colder climates.

DEF (Diesel Exhaust Fluid)

As the 2018 Tesla Model S is an all-electric vehicle, it does not have an internal combustion engine and therefore does not require Diesel Exhaust Fluid (DEF).

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