Coolant sensor

I am looking for a coolant temp sender that is closed when coolant is cold and opens when coolant is warm. Around 150 to 170 degrees.
Does anybody know where I could get one?

Do you want vacuum , or electrical? Vacuum, would be a thermal valve switch. If so, the local Napa/Carquest ignition illustration paper catalogs have open and close numbers.Your description is vague, talk to us more with description.