In a message dated 3/2/04 10:44:45 PM, vanagon@ASTOUND.NET writes:

<< I also considered drilling a small 1/8 hole in the metal of the thermostat
because I notice it seals absolutely shut. >>

Don't waste your time: the thermostat housing gets filled from both sides.
Anyway, if it needed a weep hole, you can rest assured that VW would have
punched one in the thermostat plate.

All these suggestions to put pressure or suck on the coolant system when
filling it demonstrate a lack of understanding about what is happening.  Looking
under a Vanagon will reveal the tortured route the coolant lines have to
follow.  The facts of life in this scenario are that air is less dense than water
and air is a compressible fluid while water is an incompressible fluid.  There
are several places in the coolant system where air pockets can form which will
be unrelenting and sorta invisible to any pressure or vacuum they might see.

The solution I found to purging ALL the air from the coolant system is to
rely on the laws of nature which rule the palpable universe.  First, get the van
up at the front at least the height VW specifies.  Jacking the van to this
height can be risky for the average shadetree type, but, finding a suitable
gradient to avoid hoisting the van is not impossible.  Looking around armed with
some mason's twine and a line level should reveal one.

Secondly, install an additional vent at the highest point of the system.

Thirdly, at the rear of the van, connect a temporary filling reservoir well
above the elevation of the highest point in the system.

There are some other minor things which make the job a little neater to do,
but are not essential such as attaching another temporary reservoir to the
radiator vent.

George