After I have been driving for a while and my engine has had sufficient time to heat up, my car begins to overheat while idling. As soon as I accelerate, the thermostat needle falls back into the mid-range.
This problem was previously diagnosed as a bad water pump. I had the water pump replaced a year ago and it fixed the problem, up until recently when the same exact thing started occurring again.
Is is possible that my water has gone bad again? If so, is there another issue that may be causing this? I don't want to have to replace it every year!