I took the thermostat out and there was a metal disc in the hose coming out of the bottom. Can anyone enlighten me as to what it is there for?<br/>Also, the thermostat seemed to be open and it is about 65 degrees . I have had thermostats out of <br/>John Deere and Intermational tractors but never one of these, i'm Not sure I understand what i'm Looking at. Any help or...