old thread bump...

Just discovered this as well. 01 X5 3.0, Expansion tank is leaking so while looking for the crack where it was leaking from, I noticed that the coolant level sensor wire was not plug. I started searching for the wire and couldn't find it, it does have a sensor, I would have expected a plug instead of an actual sensor. Oh well, I'll just replace the sensor since the sensor location seems to be leaking as well. I wish there was a plug instead of a $10 sensor.