This week my low coolant light came on. My coolant was about 3" low inside the radiator. I filled it up and checked everything for leaks NOTHING . I also went on a 280 mile drive got awesome milage and the car ran like a raped ape. So still trying to figure out why its low.
I drove it and when it warmed up bled the air out of the system and the level was up again.

1.Could the radiator cap be bad ?(Air inside?)

2.Could the 160* T stat be bad?(3 years old hyper tech)

 

I'd replace the radiator cap and then bleed the system.