[Longs]

I was reading about thermostat rated temperature and fully-open temperature. The references claim that the rated temperature is the temperature at which the thermostat WILL START to open, not be fully open, and that the fully-open temperature is 15 - 20 degrees above the rated temperature.

As an example, a 180 degree thermostat should start to open at 177 - 183 degrees, and will not be fully open until the coolant around it is 195 - 200 degrees. Are we considering this when selecting thermostats? I have a 180 in my GTO and it typically gets to 190 or 195, wondering how much I'd gain by going with a 160 degree thermostat instead.

It also makes me about claims when people say they have a 180 degree thermostat and their gauges show that they're on 180 all the time. How would the system operate in a way that keeps the gauge at the "start to open" temp? The thermostat is designed so that the coolant keeps getting hotter until it's fully open, it shouldn't be possible to keep the engine at the "starts to open" temp.

Interested in any thoughts on this one!