I have a 94 Grand Am V6 3.1. The car has been running fine, and the temp usually stays around the 1/4 mark on the guage. All of a sudden a couple of days ago while I was driving, the warm air turned to cold air from the vents, and I noticed the temperature guage going up very quickly to between
1/2 and 3/4 on the guage. I played with the heater control knob a bit but nothing worked. I did notice that the knob didn't turn quite as easily as it did before, kinda stuck a bit when going from warm to cool on the dial. After a minute or so it just changed back, and then warm air was coming out again, and the temp guage was back down to 1/4 where it usually is. This has happened 2 -3 times in the past 2-3 days. Can someone give me some advice as to what it may be. I am thinking possibly a thermostat problem, or excess air in the cooling system. If it is air in the cooling system, what would be the proper steps to flush that out myself. A friend of mine said somethiing about opening the cap, and letting the engine warm up for 10-15 minutes, and it will cycle the air out. Can someone give me more information please, or suggest another possible problem/solution. Thanks for any and all responses.Regards, KDawg