2019 Subaru Outback Coolant Capacity & Type

The 2019 Subaru Outback cooling system holds approximately 8.2-8.5 US quarts (7.8-8.0 liters) of coolant.

Quick Answer

• Total Cooling System Capacity: 8.2-8.5 US quarts (7.8-8.0 liters)
• OEM Coolant Spec: Subaru Super Coolant (Blue, HOAT - Hybrid Organic Acid Technology). Meets Subaru's coolant specification SOA868V9210 or equivalent.
• Mix Ratio: 50/50 prediluted, or concentrate mixed 50/50 with distilled water.

Capacity by Engine Option

The 2019 Subaru Outback was offered with two engine options, and their cooling system capacities are very similar:

Flush Interval

Subaru recommends specific maintenance intervals for the Super Coolant, which is a long-life type:

• Normal Duty: Initial replacement at 137,500 miles or 11 years, then every 75,000 miles or 6 years thereafter.
• Severe Duty: If operating under severe conditions (e.g., heavy towing, extremely hot climates, dusty conditions), it's wise to consider changing the coolant more frequently, potentially around 75,000 miles or 6 years for the initial change, and more often thereafter.

How to Refill & Bleed

Properly refilling and bleeding the cooling system is crucial to prevent air pockets, which can lead to overheating. For the 2019 Subaru Outback, follow these general steps:

1. Preparation: Ensure the engine is cool. Position the vehicle on a level surface. Wear appropriate safety gear (gloves, eye protection).
2. Drain (if flushing): Open the drain cock on the bottom of the radiator (usually on the driver's side) and remove the radiator cap to allow the system to drain completely.
3. Refill: Close the radiator drain cock. Slowly add the correct Subaru Super Coolant (or equivalent) to the radiator until full. Fill the reservoir to the "FULL" mark.
4. Bleeding Procedure:
   • Start the engine with the radiator cap off (or loosely on if preferred to prevent spillage, but some air will vent). Ensure the heater is set to full hot and the fan is on low to open the heater core valve.
   • Allow the engine to warm up to operating temperature. The thermostat will open, and coolant will begin to circulate.
   • Watch for air bubbles to escape from the radiator filler neck. Squeeze the upper and lower radiator hoses several times to help dislodge air pockets.
   • Maintain the coolant level in the radiator by topping up as needed. Be patient, as this can take 15-30 minutes or more.
   • Once no more bubbles are visible and the coolant level stabilizes, install the radiator cap.
   • Subaru Specific Tip: Some Subaru models benefit greatly from using a vacuum-fill tool to completely eliminate air from the system, especially after a full drain. This can be the most effective method to ensure a bubble-free system. Without a vacuum filler, multiple cool-down and top-off cycles of the reservoir may be necessary over the next few drive cycles.
5. Final Check: After the engine cools, check the coolant level in the reservoir and top off to the "FULL" mark if necessary. Monitor the coolant level over the next few days.

Common Cooling System Issues for this Generation (2015-2019 Outback)

While generally reliable, the 2015-2019 Subaru Outback (5th generation) can experience some cooling system-related issues:

• Head Gasket Leaks (less common than older generations, but still possible): Though significantly improved since earlier Subaru generations, head gasket leaks can still occur, leading to coolant loss, overheating, or external leaks. Symptoms include white exhaust smoke, coolant disappearing without external leaks, or oil in the coolant.
• Radiator Leaks: Over time, radiators can develop leaks due to age, road debris, or plastic end tank failures. Keep an eye out for green or blue stains under the front of the vehicle.
• Water Pump Failure: The water pump circulates coolant. A failing water pump can cause leaks from the weep hole, bearing noise, or overheating due to reduced coolant flow. This is often replaced with the timing belt on some older engines, but on the 2.5L and 3.6L engines in this generation, it's typically driven by the serpentine belt and can be replaced independently.
• Thermostat Failure: A stuck-open thermostat can cause the engine to run too cool (affecting fuel efficiency and emissions), while a stuck-closed thermostat can cause rapid overheating. Watch for erratic temperature gauge readings.
• Coolant Temperature Sensor Issues: A faulty sensor can provide incorrect readings to the engine computer, leading to poor engine performance, gauge inaccuracies, or cooling fan issues.
• Air Pockets after Service: As mentioned in the refill section, improper bleeding of the cooling system after a drain or component replacement can leave air pockets, causing localized hot spots and potential overheating. This highlights the importance of thorough bleeding.

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