I reassembled using the old o-ring and still see the gap in the center of
the flange. The gap is even present when I assemble with no o-ring. This
seems very strange...GW says there should be no gap. I am inclined to use
some Permatex on the flange and be done with it.

I have some photos here: https://www.icloud.com/sharedalbum/#B0QGI9HKKGrwNKs

-Mark

On Tue, Jan 18, 2022 at 10:47 AM Eric Caron <ericcaron96@comcast.net> wrote:

> Hi Mark,
>
> When I took part the leaking core that had worked for a few years I found
> the O ring had expanded a bit so was thicker then when I installed it.
> Also a bit less soft.  The old core connection had a bo.
>
> So, which came first?   Did the O ring push out the core connection or did
> the softened plastic allow the o ring to expand?  Something didn’t last
> over time.
>
>
> Currently I’m not dripping just a mist that appears around the seam after
> a drive.  I wipe clean then it appears after the next drive.
>
> I’m so grateful we still fairly easily find parts like the rear heater
> core, but frankly I’d rather pay more and have it last.
>
> Of course paying more for the same failure rate would be sad.
> ERic
>
> On Jan 18, 2022, at 11:51 AM, Mark McCulley <markmcculley@gmail.com>
> wrote:
> >
> > Thanks Eric, I've emailed GW support to see what they have to say. I
> wonder
> > if the flange on the new core is thinner and more susceptible to bowing.
> I
> > will compare with the old core as well as compare the new o-ring with the
> > old one to see if they are different in any way.
> >
> > -Mark.
> >
> > On Tue, Jan 18, 2022 at 8:28 AM Eric Caron <ericcaron96@comcast.net>
> wrote:
> >
> >> Hi Mark,
> >>
> >> Yes,
> >>
> >>        I’ve posted about this same issue recently.
> >>
> >> First, I noticed a leak started for no apparent reason on a low use rear
> >> core.  I had replaced the valve some time ago with the GW metal one.
> >>
> >> I replaced the O ring but it still leaked.  I then purchased a new rear
> >> heater core and when replacing I noticed the same Bowed problem.  I
> could
> >> feel a gap in the middle and when I took off the core and inspected it
> was
> >> now in a permanent bow,not flat. .
> >>
> >> I put in another new O ring with the new core and it leaked less but
> still
> >> misted.
> >>
> >> I then took it apart and had an experienced VW friend re assemble.  I
> used
> >> another new O ring.  It seemed a better but after running the van for a
> >> short time the mist slimy feel around the edge came back.
> >>
> >> So, I’ve still not completely solved the problem.
> >>
> >> I really wish the dealers would come up with a better rear core.  It is
> >> nice that this one is cheap but no fun to keep replacing every few years
> >> and even then it often doesn’t work.
> >> The O ring also seems either of poor quality or design, or both.
> >>
> >> I like having the rear heater but I’m beginning to think about just
> >> connecting the hoses and removing the rear heater and enjoying some
> extra
> >> space.  It isn’t what I want but until a better solution is available it
> >> may be my current solution.
> >> Anyone out there with a solution for us?
> >>
> >> Eric Caron
> >> 85 GL Auto
> >>
> >>
> >>
> >>> On Jan 18, 2022, at 9:13 AM, Mark McCulley <markmcculley@GMAIL.COM>
> >> wrote:
> >>>
> >>> I just replaced a leaky rear heater core and am having an issue with
> the
> >>> flange on the new core sealing to the metal GoWesty valve that I've had
> >> for
> >>> several years. I did obtain and use a new o-ring from GW. It seems that
> >> the
> >>> new o-ring isn't compressing sufficiently--the plastic flange on the
> >> heater
> >>> core bows in the middle when I cinch down the two bolts that secure it
> to
> >>> the valve.
> >>>
> >>> Has anyone else encountered this problem?
> >>>
> >>> -Mark
> >>> '87 Westy
> >>
> >>
>
>