>
> I've never replaced one, but if I were going at this cold, I'd
> - make sure the car's ignition switch was off,
> - disconnect the battery ground cable
> - try to disconnect the sensor electrically
> - drain the coolant below the level of the sensor
> - unfasten the sensor's mechanical connection

any way he can run an ohmmeter across the connection on the sensor
itself, and check for some kind of continuity? probably supposed to be a
different reading hot vs cold?