Recently David Beierl and others offered advice on remedies for a flashing
coolant light when the coolant level in the expansion tank is normal and the
engine is not overheating.   One of the suggestions was to make sure the
coolant was not mixed too strong.   Sure enough, that was my problem.   I
emptied the expansion tank with a wet vac and refilled it with distilled water
only.   Problem solved!   No more turning the ingnition off and on every
morning to reset the flashing coolant light.  That was the amount of dilution
that worked for me  (YMMV).

John McLean   87  Vanagon  GL