I had an oil drain thread insert in one of my vans. It looks to me that
your helicoil threads are starting to come out or apart. I never saw the
insert threads I installed look this way.
Hope this helps.
Rick

On Fri, Apr 13, 2018 at 6:21 PM, Michael A. Radtke <wa7zpu@5by9.net> wrote:

> Hello,
>
> Some history first.  I owned my '84 since new.  About 20 years ago, the
> oil drain plug threads in the case stripped.  I inserted a Heli-Coil.
> From that point on, I cut a new cardboard drain plug gasket to use for
> each oil change.  One reason that I switched to cardboard was so I
> didn't have to tighten the plug very tight.  I never had a leak, until
> now.
>
> Starting with the last oil change there was a small leak.  As time went
> on it got worse, but I thought that it would fix with the next
> cardboard gasket.  It didn't.
>
> Because the shoulder on the OEM drain plug is small, I changed to an
> aftermarket drain plug with a wider shoulder.  It came with a nylon
> gasket which I then used.  It still leaked.
>
> Today, I tried a cardboard gasket with the new plug.  It still leaked.
>
> So, I took some photos.  They can be found at:
>
>    http://5by9.net/busleak
>
> In photo a13.png, starting from the center, the Heli-Coil can be seen.
> Around that there appears to be an insert in the case, perhaps steel.
> Then, the case material can be see around the insert, as well as flaking
> plating of some sort.
>
> What concerns me is the artifact at about 11:00 o'clock.  Both the
> insert and the case seem to be breached at this point.  Also, please
> notice the bubble in the plating above and to the left of the breach.
>
> Photo a14.png is from a different angle and perhaps shows the artifact
> a little better.
>
> Could oil be leaking through this breach, under the plating, and then
> out?  If not, what else could the leak be?  It's getting worse and will
> have to be dealt with.
>
> Most importantly, what is the fix?
>
> Thanks,
> Mike
>