ok so I just replaced the radiator and thermostat in my 96 Toyota Tacoma it has the 4 cyl 3rz engine. getting heat out of heater so do that mean thermo is opening ?? I ask cuz the upper hose is hot as hell but lower hose is pretty much and stays cold ???? let it idle for a bit and went for a drive no change. bled it by pumping hoses by hand at first then used a no spill got some more air out and seemed pretty well bled. but I am wondering why the lower hose is staying so cold seems to me that its not flowing but yet mass heat out of the heater???? thanks all