That is most likely a "185 degree" temp switch for a cooling fan...
It LOOKS like a temp sender for a gauge, but with the text description I'm thinking it is more a switch than a sending unit.
One way to test is to put in hot water on the stove and check the resistance (one lead to body, other lead to stud on the top) and see if it changes as it heats up, or if it simply stays the same and then all of a sudden changes when the water temp passes 185 or so...
Modified Mustangs & Fords Project Snake Charmer
2006: 2/14 Delivery by Stewart Transport, 8/15 becomes a roller, 8/26 drivetrain installed, 10/15 first engine start, 12/23 wiring completed, 12/31 body test fit
2007: 2/25 first go-cart, 4/15 leaves for paint, 8/24 paint prep begins, 12/10 paint work completed
2008: 1/7 home from paint, 2/1 titled, tagged, and insured, 3/15 interior complete, 6/2 alignment, 6/4 Graduation