Thanks for the info BradMPH . Checked coolant today- radiator full, reservoir in the middle, so nothing has changed there. That's a relief. Do you have any idea on a brand for the Performance thermo? The people at the parts store aren't very knowledgeable, so any info will help them. I may look into a temp. gauge at some point. For now a new thermo will do, and I will continue to keep an eye on the OE gauge.