My wife just called and said that when she started her car, she got the low coolant warning light that told her to shut the car down immediately (I think she got the red light). She opened the hood and said that the coolant reservoir was very low. She said that it doesn't look like it's leaking anywhere and there are no puddles under or around the car anywhere.

The engine temps have been normal too. I am going to add coolant to it when I get home and keep an eye on it. I need to change the oil too so I'll check the oil for anything as well.

Any ideas on what is going on? Anything else to check?

*All of the posts I found when I searched had to do with the sensor being bad and the reservoir still being completely full.