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
>
>