I had the same problem in my Taurus SHO (intermittent).  It seems that the
sensor passes current through the coolant in order to detect it.  If the
electrodes in the sensor are gummed up or covered with schmutz, you get
false "Coolant Low" warnings.  I don't know if this is that way the Vanagon
sensor works, though...

Brent Christensen
'89 GL Syncro Westy
'91 Taurus SHO (For Sale)
'95 Cherokee Sport

----- Original Message -----
From: Thomas Czerniak <raritat@MEGSINET.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, April 12, 1999 4:33 PM
Subject: Re: Flashing Low Coolant Light (longish)

> Tom ,
>              I had the same problem with a phantom
> problem that kept the low coolant light coming on.
> It seems that the pins that are in the sensor were
> leaking coolant past the pins themselves because
> the connector and connection points were always
> wet with coolant. Once I replaced the sensor the
> problem vanished. I think I paid about 16.00 at
> the nearest VW dealer. You can probably get it
> cheaper from one of the list vendors? Good luck!
>  Tom Czerniak   87 Westy