Car overheating and white smoke coming from the rear end

My car has been overheating. When I start my car white smoke comes from the rear ends at once, I start driving the engine heats up to around 76c after a little less than 5 minutes. Then once I've been driving for about a mile or so it hits 80c and fluctuates from 80 to 90c. Then once I make it to my destination it climbs up a little more. I've replaced the radiator fan, temperature sensor and head gaskets, still no luck.