Need a little more help folks:
I posted this morning that when I got to work I noticed the coolant boiling
in and out of the overflow reservoir.  After work, I went out check the belts
and such -- all okay.  I  replenished the coolant in the overflow reservoir
(with some bottled water since fortunately my wife had just gone to price
club abd left a case of bottled water in the van) and drove home (abot 26
miles of mostly freeway).  Temp was fine (stayed below the LED).  However,
about half way home the LED started blinking and statyed blinking the rest of
the way home.  Owners manual says this means the coolant is low.  Checked the
overflow and it was full, and totally cool.  Of course the coolant in the
main tank was hot and appeared full (hard to tell)  Belts are fine, since it
doesn't overheat the thermostadt must be fine, no obvious leaks.  I haven't
openned up the cooling system or anything for over a year. Kinda stumped  --
any help appreciated.  thanks