D15B7 motor. Car was purging and overheating turns out no coolant filled it up with water for a quick fix had no problems. Couple days later drained the water and put in coolant so it won't freeze. But now its overheating when driving. Put it in neutral it goes down. Have to keep the heat on and comstantly open it up or it'll over heat. Although i can sit at a light no problem. Any suggestions on what to check?

 

Bleed the coolant. You may have air bubbles still left in the system. Bleed til radiator fan comes on 2x.