Changing the thermostat 2000 cadillac deville

The pressure they work within is usualy information on your radiator cap or owners hand book.Your thermostat should be a 180 degree but can vary The 180 is in reference to the heat required to open them so water can flow through and be kept at a more or less constant 180.There are other temp ranges for a wide variety of applications and 180 is the standard one for most vehiclesThe radiaor and water system is pressurised to lower the boiling point of the water The higher the pressure the lower the boiling point

Most thermostats are a 195 Degree witch means when temp. of coolant reaches 195 degrees it opens to let coolant flow, unless you specify otherwise. Pressure, I am not sure i understand what you mean, Temp. wise 220 to 230 is boiling witch it will never get to unless you have a major cooling problem like bad head gasget or cracked head or something on that order.