[Drover]

I just had a similar problem with #1. If you're confident the cooling system has been properly bled and the problem persists, try a little experiment. Wait until the car gets warm enough for the fans to kick on. Then, turn off ALL possible accesories that may be drawing power -- radio, headlights, HVAC fan, everything, then turn the car off. Then, turn the key back to the "on" position without re-starting the car. Is the needle giving you a substantially lower readout? If so, you have a grounding problem, causing the gauge to receive more current than it should, in turn causing a false high readout.

I had the same problem for days. I recently had cooling work done, and the system was bled numerous times, but I was still getting a hot reading. I got suspicious when the needle would jump every time a current-drawing accessory would turn on, especially headlights and cooling fans. So then I waited to see if the fans, when they kicked on, would simply stay on or would cycle. When they cycled off with the needle reading 3/4ths, I was 95% sure the gauge was giving me an incorrect reading. The experiment conducted above confirmed it for me.