2018 Subaru Forester Fluid Specs

Quick Reference: 2018 Subaru Forester Fluid Specifications

Fluid	Type/Spec	Capacity
Engine Oil (2.5L FB25)	Subaru Synthetic 0W-20, API SN or ILSAC GF-5	5.1 quarts / 4.8L (with filter)
Engine Oil (2.0L FA20 DIT)	Subaru Synthetic 5W-30, API SN or ILSAC GF-5	5.4 quarts / 5.1L (with filter)
Engine Coolant	Subaru Super Coolant (Blue)	7.6 - 8.2 quarts / 7.2 - 7.7L
Automatic Transmission (CVT)	Subaru CVT Fluid (Lineartronic CVTF-II, Green)	12.9 - 13.2 quarts / 12.2 - 12.5L (verify)
Manual Transmission	Subaru Extra MT 75W-80	3.5 quarts / 3.3L
Transfer Case (MT)	75W-90 GL-5 Gear Oil	1.4 quarts / 1.3L
Front Differential (AT)	75W-90 GL-5 Gear Oil	1.5 quarts / 1.4L
Front Differential (MT)	Same as Manual Transmission	N/A (shared)
Rear Differential	75W-90 GL-5 Gear Oil	0.8 quarts / 0.75L
Brake Fluid	DOT 3 or DOT 4	As needed
Power Steering Fluid	N/A (Electric Power Steering)	N/A
Windshield Washer Fluid	Summer, Winter, or All-Season	2.6 quarts / 2.5L

Engine Oil

The 2018 Forester came with two engine options, each requiring a specific oil viscosity. Using the wrong oil can lead to reduced fuel economy, increased engine wear, and potential damage to variable valve timing components.

• 2.5L FB25 Engine: This engine is specified to use 0W-20 synthetic oil. It must meet API Service SN or a higher standard (like API SP) and/or the ILSAC GF-5 specification. Subaru strongly recommends using its genuine synthetic motor oil. Capacity with a filter change is approximately 5.1 quarts (4.8 liters).

• 2.0L FA20 DIT (XT Models): The turbocharged XT models require a slightly heavier 5W-30 synthetic oil. The specification remains API Service SN or ILSAC GF-5. Due to the higher stress and heat from the turbocharger, using the correct 5W-30 oil is critical. Capacity with a filter change is around 5.4 quarts (5.1 liters).

Note: Always use a new crush washer for the drain plug during an oil change to prevent leaks. The service interval is typically 6,000 miles or 6 months.

Engine Coolant

Subaru vehicles are factory-filled with Subaru Super Coolant (Blue), a Phosphated Organic Acid Technology (P-OAT) formula. It is pre-mixed and should not be diluted with water.

• Specification: Subaru Super Coolant (SOA868V9270)
• Type: P-OAT, Blue

Common Pitfall: Never mix this coolant with other types, such as standard green IAT (Inorganic Acid Technology) or orange/red OAT coolants found in other vehicles. Mixing chemistries can cause gelling, reduce cooling efficiency, and lead to corrosion in the cooling system. If the system is ever drained and refilled with a different type of coolant, a complete flush is mandatory. The first recommended coolant change is at 11 years or 137,500 miles, with subsequent changes every 6 years or 75,000 miles.

Transmission Fluid

Transmission fluid is not "one size fits all," and using the wrong type in a Subaru is a fast track to a very expensive repair.

• CVT (Continuously Variable Transmission): The majority of 2018 Foresters are equipped with the Lineartronic CVT. This transmission requires a very specific fluid: Subaru High Torque CVT Fluid (SOA748V0200) or Lineartronic CVTF-II (Green). Do not use "universal" CVT fluids or any other type of ATF. Total capacity is over 12 quarts, but a drain-and-fill procedure typically replaces only 4-6 quarts. These are considered "lifetime" fluids by Subaru, but many specialists recommend a drain-and-fill service every 30,000 to 60,000 miles, especially under severe driving conditions.

• Manual Transmission: For the rare 6-speed manual models, the factory specifies Subaru Extra MT 75W-80. Using a high-quality GL-5 gear oil of the same weight is a suitable alternative if the OEM fluid is unavailable.

Transfer Case & Differentials

All-Wheel Drive (AWD) is Subaru's hallmark, and its system of differentials and (on manual models) a transfer case requires the correct gear oil to function properly.

• Front Differential:

  • Models with a CVT have a front differential that is separate from the transmission. It requires 75W-90 API GL-5 gear oil.
  • On manual transmission models, the front differential and transfer case are integrated into the transaxle and share the same 75W-80 fluid as the transmission.

• Transfer Case (Manual Transmission Only): Requires 75W-90 API GL-5 gear oil.

• Rear Differential: All 2018 Foresters use a standard rear differential that requires 75W-90 API GL-5 gear oil.

Note: No limited-slip friction modifier is required for the standard rear differential in this model year.

Brake Fluid

The hydraulic brake system requires a high-quality fluid to operate safely under pressure and high temperatures.

• Specification: DOT 3 or DOT 4

DOT 4 fluid has a higher boiling point and is a common upgrade, but DOT 3 is the minimum requirement. The two are compatible and can be mixed. Never use DOT 5 silicone-based fluid, as it is incompatible with the seals and components of a system designed for DOT 3/4. Brake fluid is hygroscopic (absorbs water), so it should be replaced every 30,000 miles or 30 months to prevent corrosion and maintain braking performance.

Power Steering Fluid

The 2018 Subaru Forester is equipped with an Electric Power Steering (EPS) system. This system uses an electric motor to provide steering assistance instead of a hydraulic pump and fluid. Therefore, there is no power steering fluid to check or change.

Windshield Washer Fluid

Use any standard automotive windshield washer fluid. You can choose a "bug and tar" remover for summer, a "de-icer" for winter, or a general-purpose "all-season" mix. The reservoir capacity is approximately 2.6 quarts (2.5 liters).

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