I have noticed my car's temp gauge would be at the half way mark then it would creep closer to the red zone then get to the red zone and the low coolant light and check guages light would go on then within about 10 seconds the temp guage would go down slowly and get to the half way point and sometimes a little lower. I checked the coolant level and it was fine. This has been going on for awhile now but not every day. Today it did the same exact thing, temp guage went to the red point and it would not cool down. I then noticed steam/smoke so I pulled over and popped the hood. It was making a sizzling sound by the area where the battery is located (total opposite side of where I would think the steam/smoke would be coming from). I did see a little bit of coolant on the ground; about the size of a half-dollar and that was it. I waited about an hour and checked the collant level and needed to pour more into it. I started the car and drove it about 10 minutes and pulled over again and it wouldn't start. About 5 minutes later it started up and I drove it home only for the car to really start steaming/smoking.I just checked the coolant level (approx 3 hrs) later and it is ok. What would be causing this problem? It is frustrating and knowing my car is not reliable is scary! Please help!