Question, for winter driving it is suggested to use a grill block of sorts to help the engine come to optimal temperature. Which monitor on a ScanGauge II would be the best to monitor so as to not over-heat the engine while also keeping one informed to operation temps? Would one just want to watch the "ICE" heat gauge or monitor the "Coolant" temperature?. In the midwest here it is not unusual to have some days that the outside temperature may vary by more than 40 degrees (F) so I would like to keep a bit of an eye on engine temperature if I'm going to be blocking the grill in the winter. I think (the first time is the hardest) that one should attempt to keep the engine operating at temperatures between 150-195 degrees Fahrenheit, is that about right?
If it's less than 50F outside your chances of overheating anything are practically zero (I'm sure someone could find some way to stress the vehicle that would prove that statement wrong, but it'll take some concerted effort). I would recommend just monitoring the ICE temp. If it exceeds 200F you're probably getting a bit too hot and should remove a block or two. The other reason to use it is that when you reach 157F you know you'll be able to go into S4. (see "stages of hybrid operation")
