I went to NAPA for a 180 thermostat and was given a "SafetyStat." Didn't open the box. Got it home and found it is the type that once heated past a certain temperature will remain open and must be replaced. There is no specification as to what temperature "overheat" is but it seems to me that on my truck pulling a grade in summer when, not if, the temperature goes over 212 the safetystat may fail open. I'm going to return it for a plain one if they have it.
