I drove all day today & there was oil in the car & water in the radiator. The car was fine until about 6 pm & then all of a sudden it was all ther way to H. I parked the car & looked & the water was boiling in ths overflow.It looked like there was a little steam from the radiator as well.I had to go inside & later I looked at the overflow. It was a little low on water so I put more water in because I had to get home. I've noticed a little fluid on the ground when I park, but it doesn't over heat until late in the day. What do you think... thermostat, water pump, fan....? I'm going to have someone look at it because I don't have a lot of money for a diagnosis,,,but, I sure don't want to hurt the engine by overheating.The car is a 2008 chevy Aveo with about 70,000 miles. I think I have a leak in the AC unit as well because all the freon is gone from last summer & we just filled it last summer.