I changed my coolant October of last year at 54k miles, from regular stuff to the orange long-life stuff. I flushed it out pretty good in the process. Drove it all Michigan winter with no problems except the temp gauge was always on the low side compared to before, between "N" and "O." of "NORMAL."
Now the weather is warming up and the temp gauge seems to be changing from day to day. It has 61k miles now. Sometimes it barely makes it pass the normal range, other times it goes up to the "R." More often than not it still goes up to bewteen N and O. It doesn't seem to change much during the drive except for couple times when it did move to as far as the "A" then back. That was in heavy city traffic but it worried me. I would like to know what may cause this and if it's a problem. The water pump is still original, but I don't think it's the problem because it hasn't overheated and most of the time it's very cool. A sticky (but not stuck) thermostat perhaps? I do plan to change it to the metal impeller kind when I fix this erratic gauge problem.
