2017 Subaru Outback Coolant Capacity & Type

A 2017 Subaru Outback holds between 7.6 and 9.5 quarts (7.2 and 9.0 liters) of coolant, depending on its engine. Ensuring you use the correct type and amount of coolant is fundamental to the health and longevity of your Subaru's boxer engine.

Quick Answer

• Total Cooling System Capacity: 7.6 to 9.5 quarts (depending on engine option).
• OEM Coolant Specification: Subaru Super Coolant (Blue). This is a Phosphated Hybrid Organic Acid Technology (P-HOAT) coolant. The genuine Subaru part number is SOA868V9270.
• Mix Ratio: 50/50 mix of coolant and deionized water. The OEM fluid is sold pre-mixed.

Capacity by Engine Option

The 2017 Outback was available with two engine choices, each with a slightly different cooling system capacity. Always allow for slight variations when filling.

Flush Interval

Subaru's blue Super Coolant is a long-life fluid, but it doesn't last forever. Adhering to the replacement schedule is key to preventing corrosion and cooling system failure.

• Normal Service: The first coolant change is recommended at 11 years or 137,500 miles. Subsequent changes should be performed every 6 years or 75,000 miles.
• Severe Service: If you frequently tow, drive in extreme temperatures, or do a lot of stop-and-go city driving, consider a more frequent interval. A good rule of thumb for severe use is to change the coolant every 30,000 to 50,000 miles after the initial factory fill has been replaced.

How to Refill & Bleed

Subaru boxer engines are known for being susceptible to air pockets in the cooling system, which can cause overheating. A proper bleeding procedure is critical.

1. Drain: With the engine cool, place a large drain pan under the radiator and loosen the petcock on the bottom.
2. Fill: Once drained, close the petcock. Remove the cap from the small expansion tank located on top of the engine (not the plastic overflow reservoir on the side). Slowly fill the system with the 50/50 coolant mix.
3. Bleed: The most effective method is to use a spill-free coolant funnel (e.g., a Lisle funnel). Attach the funnel to the upper expansion tank opening and fill it about halfway.
4. Run Engine: Start the engine and turn the heater to the highest temperature and fan setting.
5. Purge Air: Let the engine idle. You will see air bubbles coming up into the funnel as the thermostat opens and the system purges itself. Squeeze the upper radiator hoses occasionally to help move air pockets along. Continue this process for 10-15 minutes, or until the bubbles stop and the cooling fans cycle on and off.
6. Top Off: Shut off the engine and let it cool completely. Remove the funnel and top off the expansion tank to the full line. Also, ensure the plastic overflow reservoir is filled to the "FULL" mark.

Common Cooling System Issues

While generally reliable, the 5th generation (2015-2019) Outback can experience a few common cooling system issues as it ages:

• Radiator Leaks: The plastic end tanks crimped to the aluminum core can develop cracks or leaks over time due to constant heat cycles.
• Water Pump Failure: The water pump is a wear item. While not as common a failure point as on older Subarus, it can leak or its bearing can fail, causing a whining noise. It's often replaced preemptively during a timing chain service on the 3.6L or with major service on the 2.5L.
• Thermostat Malfunction: A thermostat stuck closed will cause rapid overheating, while one stuck open will result in the engine taking a very long time to warm up and poor heater performance.
• Head Gasket Seepage: Though significantly improved from past generations, the boxer engine design can still be prone to external oil or coolant seepage from the head gaskets. Unexplained coolant loss without any visible leaks can be a symptom that requires further diagnosis.

If you're experiencing overheating, coolant leaks, or are simply due for a coolant flush, it's important to have the work done correctly.

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