[s-cars] X-plugs, O-rings, and Pentosin... all over the place!

[Varon H. Fugman]

Can't get my X-plug to stay fixed!  In the 4 1/2 years I've owned the car,
it has failed 3 different times... and this time I'm having trouble getting
it to stay fixed.  I'm going through Pentosin faster than gasoline!

A brief history:

4 years ago: X-plug began seeping.  Had my mechanic repair it with an O-ring
he had.
2 years ago: X-plug let loose with a major shower of Pentosin while my wife
was driving the car.   Ordered the Audi part with new X-plug and O-ring and
replaced it myself.
2 weeks ago: X-plug began seeping, got worse.  Replaced with generic rubber
O-ring from FLAPS.
2 days ago: Started leaking again.  Replaced with another generic O-ring.
2 hours ago: Started leaking again on the way home.  Lost all fluid a block
from home, coasted home and into the garage (good thing it's down hill!)

I did stop at an import auto shop today and aquired a blue O-ring that is
made for R134 A/C systems... will this work any better than a plain rubber
O-ring?

Has anyone found an O-ring of the proper size and composition?

The Audi replacement part (x-plug + o-ring) only lasted me 2 years, so I'm
not very impressed with that.  Then again, 2 years is a lot better than 2
days!

Will the blue O-ring work any better?  How about a green one?  It would
match the Pentosin 11s... and my Emerald exterior!  Green ones are
designated for R-12 A/C systems, but since R-134 is reputed to be leaker, I
figured the best bet was with a blue one.  But what I really need is one
compatible with mineral hydrolic fluid!  Ideas?

Varon
'95 S6 spoutin' Pentosin all over the place!