If coolant level in the pressurized system can in any way what so ever be
affected by parking angle you have a problem. You have a combination of a
leak somewhere along with a defective pressure cap.  The possible leak can
also include combustion gases getting into the cooling system.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Cunegonde
Sent: Thursday, May 05, 2011 3:03 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Temp Gauge High on Startup + Blinking Light

Thanks for the info, you all. No more blinking or false high temp now.
I removed, cleaned (there was crud on the inside-the-coolant-tank contacts),
replaced, and tested the sensor. Specs are 31k-65k Ohms with tank full of
50/50 coolant/water: (http://www.vanagonparts.com/tech_bulletins.html#013
#90 92-03) Mine's at 44k Ohms. It's probably the original sensor from the
factory.

I think the problem began bcse Cunegonde is usually parked pointing forward
steeply downhill. If I filled the coolant tank completely, and the overflow
(behind the license plate) tank was also at max, it would all overflow when
the van was parked on the flat, much less facing the other way. So the
coolant tank was chronically low. Hence sensor electrodes with dried crud.
I check the cooling system every time I open the rear hatch, since my very
first mechanical experience with the van was a failed water-pump engine
overheat. Now, I'll just keep the overflow (license plate access) tank on
the low side, but the main tank at max.