mine was exactly the same way, right before my wp went. Since I changed the water pump, the needle never moves past r. And that is if I'm driving it really hard. Usually it stays right on the o. I would very seriously consider changing the waterpump RIGHT NOW!! Even if you were not experiencing symtoms yet, it should be done. The plastic impellar wp's usually only last about 50,000 miles before going. Since you're past that... Such an easy thing to do, so cheap, and could save you so much in the long run. also, if the temp goes up and then all the sudden drops back down (much quicker than the fans could cool it down) then this is def. your wp. I'm not trying to definatly diagnose, or scare anyone, just trying to help.
