Here's the deal. I have a JDM B16. The motor was running on cold while driving. So I replaced the thermostat, or lack there of, with a jackson racing 160 degree thermostat. My car didn't have a thermostat when I pulled the housing apart. Now I can let my car idle all day long and the temp reads normal. I start driving for a little while and the temp goes up. As soon as I crank the heat to high it drops immediatly. I hard wired the fan and it does the same thing. I have bled the system numerous times and that has not help either. Any ideas????