2015 Subaru Outback Fluid Specifications

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Quick Reference: 2015 Subaru Outback Fluid Capacity Chart

Fluid	Type/Spec	Capacity
Engine Oil (2.5L H4)	0W-20 Synthetic, API SN / ILSAC GF-5	5.1 US qt (4.8 L)
Engine Oil (3.6L H6)	5W-30 Synthetic, API SN / ILSAC GF-5	6.9 US qt (6.5 L)
Engine Coolant	Subaru Super Coolant (Blue P-HOAT)	7.6 - 8.2 US qt (7.2 - 7.8 L)
CVT Fluid	Subaru Lineartronic CVTF-II	~6-7 US qt (Drain/Fill)
Front Differential	75W-90 API GL-5 Gear Oil	1.4 US qt (1.3 L)
Rear Differential	75W-90 API GL-5 Gear Oil	0.8 US qt (0.75 L)
Brake Fluid	DOT 3 or DOT 4	As needed (~1.0 L flush)
Power Steering	None (Electric Power Steering)	N/A
Washer Fluid	Standard Washer Fluid	~1.0 gal (3.8 L)

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The fifth-generation Subaru Outback, launched in 2015, is a robust and capable vehicle known for its Symmetrical All-Wheel Drive and Boxer engines. To maintain its legendary reliability and performance, using the correct fluids and lubricants is not just recommended—it's critical. As an ASE-certified master technician, I've seen firsthand how using the wrong fluid can lead to catastrophic, and expensive, failures. This guide details every factory-specified fluid for your 2015 Outback to ensure it serves you well for years to come.

Engine Oil

The Boxer engine is the heart of your Outback, and the correct oil is its lifeblood. The 2015 model year features two distinct engines with different oil requirements.

• 2.5L FB25 Flat-Four: This engine requires 0W-20 synthetic oil. The factory specification is API Service SN or ILSAC GF-5. Modern oils meeting API SP or ILSAC GF-6A are backward-compatible and offer superior protection against wear and low-speed pre-ignition.
  • Capacity: 5.1 US quarts (4.8 liters) with a filter change.
• 3.6L EZ36 Flat-Six: The more powerful 3.6R model demands 5W-30 synthetic oil. The specification is the same: API Service SN or a suitable equivalent. Conventional oil is not recommended.
  • Capacity: 6.9 US quarts (6.5 liters) with a filter change.

Technician's Notes: Always use a high-quality synthetic oil. The FB25 engine, in particular, can be sensitive to oil quality and level. Check your oil level at every other fuel fill-up. Using a viscosity other than what is specified can interfere with the variable valve timing system and affect fuel economy and performance.

Engine Coolant

Subaru utilizes a specific, long-life coolant formula to protect the aluminum components of the Boxer engine.

• Type/Spec: Subaru Super Coolant. This is a blue, Phosphated Hybrid Organic Acid Technology (P-HOAT) coolant. The genuine OEM fluid is part number SOA868V9270.
• Capacity: The total system capacity varies slightly between the 2.5L (7.6 qts) and 3.6R (8.2 qts) models.

Technician's Notes: This is not your average coolant. Never mix Subaru Super Coolant with other colors or chemistries (e.g., green IAT, orange Dex-Cool OAT, or even other "Asian" P-HOAT coolants like red/pink). Mixing them can cause a chemical reaction that leads to gelling, clogging coolant passages and causing severe engine damage. If you need to top off, use only Subaru Super Coolant or distilled water in a pinch. The initial service interval is long (over 100,000 miles), but subsequent changes should occur every 60,000 miles.

Transmission Fluid (CVT)

This is arguably the most critical fluid in your entire vehicle. The 2015 Outback is equipped with a Lineartronic Continuously Variable Transmission (CVT) that requires a very specific fluid.

• Type/Spec: Subaru Lineartronic CVTF-II (Part Number SOA427V1660). While the 3.6R uses a "High-Torque" version of the CVT (TR690) and the 2.5i uses the TR580, the specified service fluid is the same. Always verify with your owner's manual or dealer, but this is the correct fluid for nearly all 2015 models.
• Capacity: A typical drain-and-fill procedure will replace 6 to 7 US quarts. A full system flush is not a DIY-friendly job.

Technician's Notes: DO NOT USE UNIVERSAL OR MULTI-VEHICLE CVT FLUIDS. The claim that these fluids "work in all CVTs" is a dangerous generalization. The frictional properties of Subaru's fluid are precisely matched to its chain and pulley system. Using the wrong fluid will inevitably lead to torque converter shudder, slipping, and complete transmission failure. This is a non-negotiable, OEM-only fluid.

Front & Rear Differential Fluid

Your Outback's Symmetrical AWD system uses both a front and a rear differential, which require their own gear oil service separate from the transmission.

• Type/Spec: API GL-5 75W-90 Gear Oil. This is a standard specification, and many high-quality synthetic brands are available.
• Capacity:
  • Front Differential: 1.4 US quarts (1.3 liters).
  • Rear Differential: 0.8 US quarts (0.75 liters).

Technician's Notes: Many owners forget these fluids exist. The front differential fluid is often neglected because it's located on the transaxle, but it has its own drain and fill plug separate from the CVT fluid. Servicing these fluids every 30,000 to 60,000 miles is cheap insurance to protect expensive AWD components.

Brake Fluid

Brake fluid is hygroscopic, meaning it absorbs water from the atmosphere over time. This lowers its boiling point and can cause corrosion in the brake lines and ABS module.

• Type/Spec: DOT 3 or DOT 4 brake fluid. DOT 4 has a higher boiling point and is a good upgrade, but either is acceptable. Never use DOT 5 fluid, as it is silicone-based and incompatible.

Technician's Notes: Brake fluid should be flushed and replaced every 2-3 years, regardless of mileage. If your brake fluid reservoir is low, it usually indicates that your brake pads are worn, and the calipers have extended to compensate. Don't just top it off—have your brakes inspected.

Power Steering Fluid

The 2015 Subaru Outback is equipped with an Electric Power Steering (EPS) system. It uses an electric motor to provide steering assistance, completely eliminating the need for hydraulic fluid, pumps, and hoses. There is no power steering fluid to check or change.

Windshield Washer Fluid

Any commercially available windshield washer solvent is acceptable. For climates with harsh winters, select a fluid with a de-icing agent and a low freezing point (e.g., -20°F or lower).

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