Hello! I am new to owning a used 2010 Subaru outback. I got the car in Sept 2019. I'm am not at all car knowledgeable. An older couple owned it before and I bought the car at 72,500 miles. Around 85,000 miles I started having an overheating issue but it didnt overheat everytime I drove it. I also started to hear a "swooshing" in the dash area of my car whenever I made a turn or came to a stop. I got the thermostat changed and did the bleeding to get the air out of the hose-I looked it up in YouTube. It seemed like I had to put a lot of anti freeze in the truck as well. Even after I would fill it up the next day when I would check it would need more. The car had been running fine but after a few days, coolant levels good, then "swooshing" sound came back and the car started overheating yesterday. All that to ask, could this be a head gasket issue?