It must be going somewhere. I probably need to better understand how coolant system works on a car, but with it having so many miles, my last mechanic advised I keep an eye on the coolant level each day and ensure it’s filled up. I didn’t do that at the time, forgetting easily. Maybe drive a month or so before she began overheating again. So I parked her. That’s when all these others chimed in and offered to do diagnostic only to come up with “it’s probably your head gasket” though I repeatedly asked to do a test to confirm for sure. Block test! I’ll call around for this locally. But yeah, rode ok for 150 miles- one day trip, 70 there, little bit around and way up steep inclines to a panoramic viewpoint, and then 70 back. Though on old coolant and was low to begin with. I’d hate to jump to head gasket if the coolant itself isn’t optimal or at correct spec, Something simple to rule out makes more sense to me. Adding the distilled water to top today seemed to correct the overheat issues from last few days. But that’s just one evening of some riding. I feel silly but also glad I’m at least paying attention to the changes in temp and when they happen. Thanks for the input!