At 09:10 AM 6/7/2002, Ed Carroll wrote:
>But the question is this: How do I know the system is truly properly bled?
>Are there characteristics of this tangle of plumbing that I'm overlooking
>that would somehow not be reached by cold pressurization? I have opened
>the bleeder at the thermostat housing and always get coolant -- no air,
>but I have still not lifted the front end of the van for this process. Am
>I kidding myself here?

I think you are, though I can't prove it.  The point of raising the front
is to make the radiator the highest point of the system, and have the air
floating uphill into the radiator so it can be purged.  This system has
long horizontal runs that are depressed below both engine and radiator, so
any air trapped in the engine is going to want to stay there.  The
combination of raising the front end -- and running the engine fast so the
pump gives plenty of circulation -- and having it up to temp because
otherwise the return flow from the radiator is blocked, preventing
circulation -- and opening the curious little bleed valve (at least in
1.9s) that bleeds bubbles from the radiator feed line into the radiator
return line -- is what VW has determined works to bleed this...er...curious
system.

I have to say that looking at the flow diagram in Bentley makes my head
spin.  I would dearly love to hear a knowledgeable explanation of a)
exactly what all  the bits and bobs in the 1.9l system do and b) the effect
of the changes in the 2.1l system.  Argh...

david

--
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"