I have a 2002 Ford Focus.
Whenever the car is idling the heat gauge goes up at an alarming rate and goes the farthest into the red that it can if left alone.
Now if I rev the engine a little the temperature goes down (no matter the gear), I took it to a couple of mechanics and they couldn't figure it out.
What could be causing this, and how would I fix it?
As per Tester101's comment I went to my car and checked some things out, here's what I found.
I let the car sit in park for a couple of minutes, so for around 10 minutes the needle stopped at the midway point, after 10 minutes it started going up and the fan didn't turn on. When the needle was at the highest it can go and I was about to shut the car off I heard the fan go on.
I let it go for 5 more minutes but the needle still didn't go back down from the highest.
Anyway I turned off the car for 2 minutes and when I turned it back on, the needle was just starting to go into the red however the fan was on. Even though the fan was on it still kept getting hotter.