Hello.
I have a 2001 Grand Prix SE, approximately 125,000 miles.
Today, while I was driving home from work, the High Temp light came on; the gauge was at about 3/4s of the way up when I noticed. My commute, with traffic, takes roughly an hour each day and it is pretty warm out (87 with high humidity), so I was running the AC at full blast with temp at max, as I have done for the last few weeks. Once I got near to being home, I noticed the air coming out of the vents was a bit warmer than what it should be. When I looked at the temp gauge, the TEMP light was on. I immediately turned off the AC and just cranked up the heat full blast. Almost immediately, the gauge dropped back down to half and the light went out. When I got to the house, before turning off the car, I turned the AC back on and cold air was coming out of the vents. I let it run for a few minutes and the gauge never moved up.
I shut off the car and looked around underneath to see if fluid was dripping on the ground and saw nothing. I let the car cool down for about 45 minutes and went and checked the coolant level and everything is A-OK with that.
Any idea what could cause something like that? Is possible it was just a result of a really warm day and lots of idling in traffic?
I should note, the car didn't actually over-heat and there was no steam coming from under the hood. I'm a little concerned about this, though, because it's never happened until now. Just this past Monday, I took my car in for an oil change over lunch (Jiffy Lube) and the tech recommended I have the radiator flushed, so I had them do that, as well. Now, a few days later, this happens. Maybe it's just coincidence.
Anyway, any thoughts or ideas would be appreciated.