Okay .. I know I have posted before asking about safe temps for my 97 deville but I have to ask again. Yesterday I drove to my parents house for Easter .. left around 10am but it was already warm and humid and the A/C was on AUTO and 71 as usual. It was a little more than 80 degrees outside and very humid. I was moving along at around 75 or so and I decided to speed up ... I nailed it and was going about 97 when I noticed the coolant temp raise steadily from 206 up to 233 ... this happened in about 20 seconds time. I slowed down a lot and it went back down to around 217 and hung there most of the remaining trip. I drove about 60 miles one way to my parents. I didn't go over 75 or so after that happened and was scared it was developing a problem. There was quite a bit of stop and go traffic (which I drive in on a daily basis). I have driven 97 and much faster many times before and never saw the temp get close to that. Last evening when I left for the trip home it was about the same temperature outside and still humid. The temp ran around 217 again for a lot of the trip .. I was in stop and go again and it spiked up to 230 this time ... I was only going around 60mph this time. It then went back down to around 212 until I got home. Traffic wasn't as heavy this time and I was moving most of the time. The coolant level is normal and the oil is full. It was hot again this afternoon and I took my regular trip down I-4 in stop and go to and from work. It never went about 206 today. I do NOT understand this car. I know I seem to worry a lot about this but I am totally paranoid that it will run hot and I will blow a headgasket. Is this normal? What signs should I look for before stopping (other than the warning lights). I guess what I want to know is what is the highest temp I can drive at before I pull over and idle to cool down? Thanks again Everyone!!