I have had mostly good things with my car, but last summer (2014) I was told there was a slight leak in the head gasket and told to watch leakage, that a new one would eventually be needed. I was also told I needed bushings and they needed to replace the whole axle as they don't just do bushings. Luckily, my cousin works on cars and said to bring it to him when I visited the family (he's in another state). He looked over everything and said there was NO way I needed either, and that based on my mileage (130K), it was normal to have a little leakage when I was doing a lot of driving (mostly highway). The bushings had no cracks and were still pliable, also, so those still had a lot of wear yet. If you can find a good old-fashioned honest mechanic in your area, go to them - they will do right by you. I had one, but he lost everything in his divorce, and I had no choice but to go to the dealer for one item, that then netted me the other advice. I am glad I didn't follow it and will now see my cousin for everything if possible!
Sometimes exhaust pressure will get into coolant from a bad head gasket. However I would be very suspicious of a DX of a head gasket on a vehicle unless it runs really hot for no reason and you find excessive pressure from exhaust heat in the coolant. I had that problem so bad that within 3 minutes of running the engine the temp gauge for coolant would be over 3/4 hot and before I could get out of the car and open the hood I could actually hear the pressure and see bubbling in the overflow tank. I did not have any excessive oil usage, loss of power, or smoke coming out the exhaust, but I was using coolant and the engine did overheat about 2 month before the problem became apparent. Towing a Camper trailer with a Tribeca in that heat in just being reckless and probably could have been the cause and not a vehicle defect.
Thats what the mechanic said, bloody hard when your in a small town and theirs only about 3 other mechanics which will touch Subaru's. Will probably do it though just to make sure.