It could, when the current working temp is below the maximum thermostat threshold, which can be the case under certain conditions. I do know about the OEM temp and efficiency, though, that's true.
Anyway, is seems you guys won, this time. Here is a fresh pot test:
Both old and new stats open at the same time, and both still work ?
The car is running fine on the road, it's just I get nervous at a parking lot or the light when the needle starts to fluctuate toward the right. I know it is very likely still within specs, for these cars, but still... My radiator is clean on the outside. The system will be flushed today. Never heard about the paper trick to check the fan, will try that, thanks.