"2005 Mitsubishi Lancer Radiator Heating Problems"

Yellow 2005 Mitsubishi Lancer Left Side View

I have a Mitsubishi Lancer 2005, and there were heating problems. I tried almost everything to fix it as follows :
1- Radiator water filled : Checked
2- Fans working : Checked
3- Engine oil : Checked
4- Radiator tank water filled : Checked
5- Radiator frame not dropping : Checked
Even though I did fix all those things I still have heating problem
The thermostat may not be a problem because when the car reaches high levels the air conditioner starts to become hotter.
About the radiator tank , must it become full or at half ?
The changes very often it can reach to the middle or go up to the H level. I have put a antifreeze (although we call it green water, it does more than that)

Answer: If you are running just water in the radiator, you need to put in a 50/50 antifreeze/water mix. If your coolant level was low at any time, you have a coolant leak because you should never have to add coolant.