I was driving around doing errands all day, and everything was tickety-boo. Then, after leaving the hardware store, I realized that my temperature dial was maxed out with the warning light on. I had to drive about 500m or so before I could pull over, and just as I was pulling over, it went back to normal. I drove very lightly for the rest of the way home, and watched the dial like a hawk. Nothing happened. I thought I noticed a slight surging feeling when the light was on, with a on/off sensation from the engine, but it was very slight. Upon reading around here, I'm not entirely sure (and worried) as to what it might be. What are your recommendations as to how I should address this problem?