Greg,
Check your coolant level in the tank that is inside the engine bay with
the pressure cap (blue or black).  This light comes on to let you know
you have a low level of coolant.  If you are marginal on the level it
wants it can come on and go off on you or do other strange things.  Let
the van cool off and top off the coolant.  Do this for a couple of days
and you should be good.  If your level keeps going down you need to find
out where it is going.

Let me know if I can help you further,
Ken Wilford
John 3:16
www.vanagain.com

Gregory S. Morrison wrote:
> Although nothing seems amiss, although something obviously is, the H2O
> warning light comes on randomly for no apparent reason. Sometimes it stays
> on for a short time...then shut down Vanagon....then restart Vanagon and no
> warning light. Two days ago it came on and stayed on continuously for the
> commute to work. Today it came on briefly during startup (normal) and didn't
> come back on again.
>
> Any thoughts or suggestions?
>
> Thanks,
> Greg
> 86 Syncro Westy
>
>