E36 M3 low coolant

["Andrew D.Mendez" <AMENDEZ@xxxxxxx>]

My car (after 22 months in use & 24,000 miles)
gave me the "coolant low" signal last month. It
only needed about one Rolling Rock of fluid (I
used distilled water instead) to be back to the
"full cold" mark. At first, drawing upon my vast
reservoir of high school science knowledge, I
suspected the low level was due to the cooler
temperatures we have with the coming of fall
(Newton's 6th law of thermodynamics is that all
matter -- except for nipples -- contracts when
cold & expands when hot). But then I remembered
the coolant level was fine when I bought the car
in January when it was much colder, so I figure
there was some evaporation or that 9 months of
hard driving used some up. My uneducated guess is
that this is entirely possible without any
leaking/anomaly, but someone with a modicum of
technical knowledge should weight in on this. 

Andy '95 M3