Coolant temperature light

[Danton J.A. Cardoso]

Ok, it has been in the single digits overnight and sometimes negatives here
in MO.  My car (B5 A4 with a 2.8 litre), unfortunately has to sit outside-at
least its in a carport, upon morning start up, the coolant light will flash
and beep.  I immediately shut it off, and start it again, no coolant light
flash and beep the second start up.

Today, it did the same thing, and on the second key turn, it did it again.
Checked coolant about .25 of an inch below MIN mark.  Slowly drove over to
Wally-world and topped it off with distilled water- I had to run an errand
that involved a 60 +/- round trip drive at highway speeds.  This only
happens when it is very cold.  Heat is good, temperature gauge does go up to
mid.

Thoughts?

 

Danton J.A. Cardoso