I just drove mine from Portland to Fordyce and back and it was doing something similar. It would run at the normal temp then start climbing. I'd stop for gas and let it sit for only 5 mins. and it would be in the normal range again. Sometimes it would start getting hot then the gauge would just drop right back into the normal range. I flushed coolant cuz it was knarly lookin
but it was still doing it, looked like previous owner had used stop leak and I was thinking thermostat maybe sticking. And it wasnt getting hot as soon as I started driving, it would be like an hour later.
