Well, my memory is fading on the SLO, but the SHO housing has two sensors near each other under the throttle body. The closest one will have a 1 wire (dash cluster) connection like the oil cooler. The one tucked a little further is a two wire (computer). If the computer one was missing, this would lead to the fans not turning on unless the A/C was cycled. I don't see any danger with this testing. It's going to let you know if there are issues at your cluster gauge. My hypothesis, without the backplate on the thermostat, there is potential for heated water from the engine to turn back around into the engine and not get cooled. However, it's just as probable that the cold water mixes with the supplying hot water headed to the radiator and helps to cool it more. The SLO does not support the backplate, so it's possible somewhere down the line you may have gotten one of those. I know I have had issues with the wrong reservoir and A/C compressor. Some of the systems don't do a good job of ensuring the part is correct for the engine. I agree that 180°F is the sweet spot between the engine not being too cold, and efficient burning of the fuel (< 210°F).