or did my coolant sensor death just coincided with running straight water in coolant system?

 

sounds like a coincidence. Btw i would recommend adding some Wetter Water if you are running straight distilled water.

 

Coincidence. Why would you run straight water anyway? Heck I had a lot of rust in my motor when I pulled it and it got flushed every year with FL22. I was very surprised, I can only imagine the rust with straight water.

 

Coolant has more lubricity than water......so it is possible the sensor has stuck with the water. Not like it wasn't going to crap out eventually though

 

has anyone done a CLR treatment of the coolant tank?

 

I recently flushed my coolant and refilled with an 80/20 water to coolant mixture, and shortly after my coolant light came on. After not being able to figure out the cause I just unplugged the sensor and now I just check the level a few times a week.