I have changed out the t-stat, radiator and water pump on the car and its still trying to overheat, It seems the thermostat is not opening but i tested it in water before hand and it opened up. the car got hot enough today for fan to kick in but lower radiator tube that comes from thermostat location was cool to touch so its not opening. has anyone experienced this before? there is no white smoke or bubbles in overflow tank and I am not loosing coolant. I have heat as well it just seems thermostat is not opeing