I have a 1995 Grand Prix that the temperature gauge likes to climb up to the 240-250 range. Sooner or later it comes down to way below 200. This happens especially when I'm stopped for a period of time with my foot on the brake. I keep a close eye on this all the time. Yesterday going to work, I hit the highway about 10 minutes of city stop and go traffic. Cruising at 65 mph, the gauge still climbed up to around 240 and eventually came down and stayed in the normal range. I had the car for 7 years. I keep her in pretty good running order (it runs excellent for 137,000 miles). I recently had a new thermostat and flush done to it. I'd say a couple of months ago. The coolant isn't low. I notice the 2 fans I have by the radiator only come on at certain times, I hope they come on. What's the story on them. Should they be running all the time. Do I need to be worried about my dilemna? Please help. Thanks for your time.
Del