Brian,

I'd make sure that there is (are) leaks before you act as you indicate
and change the cores. The valve in the rear heater is a known
failure-prone item.  It may be the $2.00 flat washer, or it may be the
tendency of the shaft seal to fail on the $55.00 one-of-a-kind valve..
Feel the carpets and sniff the floor for the tell-tale scent of coolant
before you act.

Somewhere in the Archives at http://gerry.vanagon.com, there is a
caution about bypassing the rear heater with the short length of pipe
arrangement.  The caveat has to do with cold coolant being introduced
into a hot part of the engine.  I can't remember the time of the
posting, or the specifics of the caution as to "what-when, " but it has
been within the past few weeks, or so.

I had to replace the valve on the heater, and I proposed to use your
approach.  I was warned by a list member of dire consequences. Review
the route, in your Bentley or Haynes, of the coolant through the engine,
and all will be clear.

As to the "tee, " it has been suggested to me that the VW boxer has
enough weak spots in its contrived-to-fit-an-air-cooled-prototype
cooling system.  Adding a "tee" would be adding another weak spot.

Tom Hanlon
Palm Springs, CA
84 Westy

Brian Doss wrote:

> Both the front & rear cores in my '88 need changing. At least I'm
> assuming so,
> since I can't immagine a hose leak etc..creating such a volume of
> loly-pop
> smell. I'm part way through removal of dash. any tips? I bought my
> vanagon
> with 100k on him, is the heater core problem common, and is it related
> to the
> phosfate free antifreeze usage? secondly, I am considering just
> temporarily
> by-passing the rear heater core (never use it) with a short piece of
> pipe.
> does anyone think it would be smart to take advantage of this bypass,
> and add
> a flushing tee here for easy access? thanks for any advice.