I have a 2012 Mitsubishi Eclipse GS Sport with roughly 67k miles on it. I got the radiator replaced and a coolant flush in September but the problem persisted, though not as bad. Took it back and got the thermostat replaced and another coolant flush in October. It didn't overheat for a good month. I drove it well over 200 miles in a day and it didn't over heat, November 4 to be exact. A week ago I drove it about 70 miles and noticed, in city traffic, the temperature gauge started to go up but it never got into the H area. Stopped and let it cool down for a hour and began driving again, once again it started to overheat, maybe 5 minutes into the drive, but not getting in the H area. I heard my fans cut on each time it got close to the H. I was stuck at a light but it began to cool down once I started moving. Drove another 70 miles and it didn't over heat at all. Let it sit idle for a good 15 minutes and it stayed at the middle line. I've been driving it 20-25 minutes back and forth to work and it hasn't overheated or anything. I do believe it's only on long trips. Any ideas on what it could be?