Overheating repeatedly

Okay, I just bought this car listed above se1 v6. The previous owner said it started running hot so she parked it, when I got it and drove it, it didn't get hot immediately but when it did I discovered the water pump was leaking. So I went the next day and got one, I put it on everything same time. So I drove it to town approximately 20 + miles and it ran hot as I got into town it immediately overheated. So I pulled over market discovered the fans were not working. So went and bought a new relay and fix that problem, but it still kept overheating to the point where I was stuck at a gas station for four or five hours ended up buying a new thermostat replacing it, getting a new into the cooling line. I even bought a code reader and it gave the code I was expecting which was for a sensor, but that's not the problem. Every few miles I'm having to stop and turn off the engine and open the bleeder valve and add more coolant and water because it's getting too hot. I know that this particular type of motor does have problems with having airport keys in the cooling v system and I go through the necessary steps to cool it down enough to drive. But why is it doing this even after replacing those parts and bleeding? It I'm stumped and am open for explanation.