2022 Subaru Forester — Coolant Capacity & Type

The 2022 Subaru Forester holds about 7.2–7.8 quarts (6.8–7.4 liters) of engine coolant when drained and refilled, depending on residual coolant and equipment.

Quick answer

• Total cooling system capacity: approximately 7.2–7.8 qt (6.8–7.4 L)
• OEM coolant spec: Subaru Super Coolant, Blue; P-OAT (phosphated organic acid technology), silicate- and borate-free; Subaru premix p/n SOA868V9270A (or superseding)
• Mix ratio: 50/50 premix from Subaru. If using a compatible Asian P-OAT concentrate, mix 50/50 with distilled water

Capacity by engine option

Notes:

• Variation depends on how thoroughly the heater core, engine passages, and radiator are drained, and whether a vacuum-fill tool is used.
• Always verify against the under-hood label or owner’s/service manual for your market.

Flush interval

• Normal service: Subaru’s long-life factory fill (Blue Super Coolant) is designed for up to 11 years/137,500 miles (220,000 km) on the initial fill, then every 6 years/75,000 miles (120,000 km) thereafter when refilled with the same Subaru Super Coolant.
• Severe duty: If the vehicle regularly tows, sees extreme temperatures, or you’ve mixed coolants/used non-OE fluid, consider shortening the interval to about 5 years/60,000 miles after the initial period.

How to refill & bleed

Subaru recommends vacuum-filling when possible to avoid air pockets in the FB-series engine.

1. Start cold and safe: Park nose-up if possible. Let the engine cool fully. Remove the radiator cap at the radiator neck (not just the overflow cap).
2. Drain: Open the radiator drain cock. For a more complete drain, remove the lower radiator hose. Collect and dispose of coolant responsibly.
3. Close and prep: Reinstall the drain and hoses. Inspect the radiator and reservoir caps; replace if seals are cracked.
4. Fill method A – Vacuum fill (preferred): Attach a cooling system vacuum fill tool at the radiator neck. Pull 20–25 inHg, verify it holds vacuum, then open the valve to draw in Subaru Super Coolant 50/50 premix until full. Top the overflow reservoir to the “FULL” mark.
5. Fill method B – Gravity with spill-free funnel: Install a spill-free funnel at the radiator neck. Slowly add Subaru Super Coolant 50/50 premix while squeezing the upper radiator hose to purge air. Fill until the radiator stays full and the funnel has some coolant. Fill the reservoir to “FULL.”
6. Bleed: Set HVAC to full hot, fan low. Start the engine and idle. As the thermostat opens, you’ll see air purge; keep coolant above the funnel neck. Allow both radiator fans to cycle on/off twice. Lightly raise RPM to ~2,000 for 30–60 seconds to move trapped air.
7. Finalize: Shut down, let it cool completely. Top off the radiator to the brim and the reservoir to “FULL.” Reinstall the radiator cap securely.

Notes:

• The FB25 typically does not use a separate bleed screw; proper fill technique is key to avoid trapped air.
• If heat output is weak or you hear gurgling after service, residual air is likely—repeat the warm-up and cool-down top-off cycle.

Common cooling system issues on this generation

• Water pump seepage: Minor weeping at the pump vent hole can start as mileage accumulates. Replace the pump and gasket if seepage becomes evident.
• Thermostat housing/O-ring leaks: The plastic housing and O-ring can seep; ensure correct torque and use a fresh O-ring when servicing.
• Radiator plastic end tank seep: With age/heat cycles, the crimped plastic tank can develop a small leak near the upper hose area. Replacement radiator is the cure.
• Radiator or reservoir cap wear: A weak cap spring or damaged seal can allow boil-over into the reservoir. Replace caps that don’t hold pressure to spec.
• Air pockets after service: Improper filling/bleeding can cause heater complaints, gurgling, or fluctuating temps. Use a vacuum-fill tool or spill-free funnel and follow the bleed steps above.

Coolant type reminders

• Use only Subaru Super Coolant (Blue) or an equivalent Asian P-OAT (phosphate OAT) formula that is silicate- and borate-free and explicitly labeled compatible with Subaru’s Super Coolant. Avoid “universal” green or silicated HOAT formulas.
• Do not mix colors/chemistries. If changing types, a thorough drain and refill (or distilled-water flush) is required.

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