I have a 2013 ford fusion se. One day I started up my car drove a mile and the car over heated. Popped the hood and saw that my coolant was low. Was like half a mile from autozone. Poured a cold water bottle I had to the reservoir. Then bought some coolant. Let my car cool down and put in brand new coolant. Seemed to fix the issue. I’m not sure how to the coolant got so low. No signs of leaks on the ground. Also no coolant in oil. As I went got my oil changed the next day. So I have been keeping an eye on the temp. Noticed a bubbling sound this morning after about a week. Coolant levels are fine. No white smoke from tail pipe. No overheating. Not sure if it’s just air in the cooling system or a blown head gasket.