It was hard. It snapped off when I tried to pull it out. It may have either blocked the thermostat from opening or jammed it open.
Now the new thermostat is in and I've got the engine hot the top of the thermostat is has hot coolant but the bottom of it with the single hose to the bottom of the rad is cold but you can see coolant in there. Also the radiator is cold apart from the very top black plastic part.
Could it be I'm not getting it hot enough to open the thermostat or is the a problem still?