Gauge went all the way right a few weeks ago. Easy job. Just had to take off accordion tube and use an extension on my socket wrench. Worst part was cleaning up all the antifreeze. A pretty substantial amount spilled out, so I'd recommend having everything ready to go as soon as you pull the old one out. 22 bucks at a local Ford dealer.
For future reference, the part # is: F5RZ10884B.
Note: not coolant temp sensor; just temp sending unit that tells gauge what to read.
