Why does my car keep overheating

If it's disappearing and not leaking out on the ground, check the oil level. If it's overfilled it's probably going to be a head gasket. If your car has a 2.7 liter it's a common problem.

Replace your radiator cap, add antifreeze mix to radiator with the engine running and with the heat on full until bubbles disappear. when you feel the heat in the cabin, replace the radiator cap. If after all that you are still loosing antifreeze mix ...there could be a leak in the water pump ..have it checked and replaced if necessary. I had the same problem turned out to be a leaky water pump.