2021 Ford F-150 Fluid Type Specs

As an ASE-certified master technician, I get asked about fluid specifications constantly. The 2021 Ford F-150 marks the beginning of the 14th generation for America’s best-selling truck. With a vast lineup of powertrains—including the 2.7L and 3.5L EcoBoost, the classic 5.0L V8, the 3.0L Power Stroke diesel, and the innovative 3.5L PowerBoost Hybrid—getting the right fluids into your F-150 is more critical than ever. Modern Ford engines and drivetrain components are highly sensitive to fluid chemistry, and using the wrong spec can lead to catastrophic failure.

Below is your comprehensive guide to the factory-spec fluids for the 2021 Ford F-150. Always verify your specific capacity in the owner's manual or OEM service info, as variations exist based on cab size, tow packages, and drivetrain configurations.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (3.3L V6)	5W-30 (WSS-M2C961-A1, API SP)	6.0 qt (5.7 L)
Engine Oil (2.7L EcoBoost)	5W-30 (WSS-M2C961-A1, API SP)	6.0 qt (5.7 L)
Engine Oil (3.5L EcoBoost/Hybrid)	5W-30 (WSS-M2C961-A1, API SP)	6.0 qt (5.7 L)
Engine Oil (5.0L V8)	5W-30 (WSS-M2C961-A1, API SP)	7.75 qt (7.3 L)
Engine Oil (3.0L Diesel)	5W-30 FA-4 (WSS-M2C214-B1)	6.5 qt (6.2 L)
Engine Coolant	Motorcraft Yellow (WSS-M97B57-A1, OAT)	11.5 - 16.5 qt (varies by engine)
Transmission Fluid	Mercon ULV (WSS-M2C949-A, XT-12-QULV)	Approx. 13.1 qt (total dry fill)
Transfer Case (4WD)	Mercon LV (XT-10-QLVC)	1.5 qt (1.4 L)
Front Differential	75W-85 Synthetic (WSS-M2C942-A)	1.7 qt (1.6 L)
Rear Differential	75W-85 Synthetic (WSS-M2C942-A)	2.7 - 3.3 qt (varies by axle size)
Brake Fluid	DOT 4 LV (WSS-M6C65-A2)	Fill to MAX line
Power Steering Fluid	N/A (Electric Power Steering)	N/A
Washer Fluid	Standard All-Season (-20°F or lower)	Fill to top
DEF (3.0L Diesel only)	Diesel Exhaust Fluid (ISO 22241)	Varies by tank (Approx 5-7 gal)

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Engine Oil

For the 2021 model year, Ford specifies 5W-30 viscosity motor oil for almost all of its gasoline engines (3.3L V6, 2.7L EcoBoost, 3.5L EcoBoost, 3.5L PowerBoost, and 5.0L V8). The exact specification is Ford WSS-M2C961-A1 and must meet API SP and ILSAC GF-6A standards. The API SP standard is incredibly important for the EcoBoost engines, as it specifically protects against Low-Speed Pre-Ignition (LSPI)—a condition that can crack pistons in modern turbocharged engines.

If you are running the 3.0L Power Stroke Diesel, you must use a 5W-30 FA-4 diesel-rated oil meeting Ford specification WSS-M2C214-B1.

Tech Tip: Ford’s Intelligent Oil-Life Monitor will tell you when to change the oil, but if you do heavy towing, extreme idling, or drive in dusty conditions, do not exceed 5,000-mile intervals. Regular oil changes are the best way to prevent timing chain and phaser wear on the 3.5L EcoBoost.

Engine Coolant

The 2021 F-150 uses Motorcraft Yellow Antifreeze/Coolant, which is a P-OAT (Phosphated Organic Acid Technology) coolant meeting specification WSS-M97B57-A1.

Warning: Do not confuse this with the older Motorcraft Orange or Motorcraft Gold coolants. Mixing OAT formulations with older HOAT or traditional silicate-based coolants will cause the additives to fall out of suspension, leading to a sludgy mess that plugs up heater cores and ruins water pumps. Stick to Motorcraft Yellow, diluted 50/50 with distilled water.

Transmission Fluid

All 2021 F-150s come equipped with Ford’s 10-speed automatic transmission (the 10R80 or hybrid variant). This transmission exclusively uses Mercon ULV (Ultra-Low Viscosity), part number XT-12-QULV, meeting spec WSS-M2C949-A.

Warning: Never use universal ATF or older Mercon LV in this transmission. Mercon ULV has a drastically different viscosity profile to reduce parasitic drag and improve fuel economy. Using the wrong fluid will result in harsh shifting, shuddering, and eventual clutch failure. The fluid is dyed red but tends to turn dark quickly under normal operation; do not judge this fluid solely by its color.

Transfer Case

If your truck is 4WD, the transfer case requires Mercon LV automatic transmission fluid (XT-10-QLVC). It is crucial to note the difference here: the transmission takes Mercon ULV, but the transfer case takes Mercon LV. Mixing these up is a common DIY pitfall. Change this fluid every 60,000 miles, or 30,000 miles if you frequently drive off-road or in deep water.

Front and Rear Differential

Both the front and rear differentials on standard 2021 F-150s call for 75W-85 Premium Synthetic Hypoid Gear Lube meeting Ford specification WSS-M2C942-A.

If your truck has a mechanical Limited Slip Differential (LSD), you must add 4 oz of Ford friction modifier (XL-3) to prevent the clutch packs from chattering during turns. Keep in mind that many F-150s utilize electronic locking differentials (e-lockers), which do not require a friction modifier. Always verify your axle tag or VIN build sheet before adding friction modifier.

Brake Fluid

Ford specifies Motorcraft DOT 4 LV (Low Viscosity) High Performance Motor Vehicle Brake Fluid, meeting specification WSS-M6C65-A2. The low viscosity formulation is critical for the proper and rapid operation of the ABS and electronic stability control systems, especially in cold weather. Brake fluid is hygroscopic (absorbs moisture), so flush your brake system every 3 years to prevent internal corrosion and soft pedal feel.

Power Steering Fluid

The 2021 Ford F-150 utilizes Electronic Power Assist Steering (EPAS). Because the steering rack is driven by an electric motor rather than a hydraulic pump, there is no power steering fluid to check or replace.

Washer Fluid

Use a standard, high-quality washer fluid. If you live in a climate that experiences freezing temperatures, ensure the fluid is rated for -20°F (-29°C) or lower to prevent the washer reservoir and lines from cracking.

Diesel Exhaust Fluid (DEF)

For the 3.0L Power Stroke Diesel, you must maintain your Diesel Exhaust Fluid level. Use only DEF that meets ISO 22241 specifications (which is standard API-certified DEF). Be careful not to spill DEF on the truck’s paint, as it is highly corrosive, and never accidentally add DEF to the diesel fuel tank.

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Proper maintenance with factory-spec fluids ensures your 14th generation F-150 will provide reliable service for years to come. If you aren't comfortable tackling these fluid exchanges yourself, leave it to a professional.

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