Ok, here is the problem, when i put a thermostat in the car it will run fine then all of a sudden it will overheat. when i take the thermostat out it never warms up past 120. here are some specs of the cooling system, griffin two row radiator, victor high flow water pump, Stewart High Performance 160 degree Thermostat and a mechanical fan. here is what i have tried; bleeding the system of air and changing thermostat. I have also checked to make sure the thermostat is functioning properly and made sure the radiator hoses were not collapsing by putting in reinforced hoses. thoughts?