Has anyone used a diagnostic scanner or any other tool to determine the actual operating temperature of our engine. I know the thermostat is 180F and usually cars operate from 210-220 but wanted to know if anyone has any concrete data. I'm trying to determine the actual operating temperature to decide on whether to use 5w-30 or 5w-40. I have heard that our VQ operates "hot," but was hoping for a more scientific answer.