If it is just the terminal broken off, rather than the sensor has gone faulty, you can fairly easily solder a wire onto it, and fit a spade terminal on that.
Mine also decided to part company just after I did my water pump, and after I struggled to easily find a replacement, I just used the Dremel to clean up the rivet that originally held the spade on, and then soldered a short wire directly onto it. I used a cable tie, and fixed the wire back onto the hexagonal head of the sensor, to stop it vibrating loose, and then put a spade on it. Once all joined back up, I folded the cable and tied it to the wires on the other sensor.
