I'm not a mechanic, so this is only an educated guess, but I'd consider
the thrust bearing as the culprit.  Had this happen on a 1.9L that had a
suspicious light tapping or buzzing sound from the flywheel end of the
engine.  During the post mortem, I realized that the noise had been made
by the crankshaft grazing against the inside of the engine case.

Karl Wolz

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
Behalf Of
> David Shepherdson
> Sent: Tuesday, January 03, 2006 12:47 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Failed Crankshaft seal yet again
>
> I just watched my 87 syncro Westfalia being winched onto a flat bed
tow
> truck for the 3rd time in 5 months near Bend Oregon this weekend, all
> three times were the result of catastrophic failure of the main
> crankshaft oil seal. I am appealing to the list now to solicit some
more
> ideas about what could be wrong before I drive back to Bend (from
> Portland, Oregon) next weekend to try and fix it.  The first time this
> happened was on a trip to NWT in Canada.  That time it was the part of
> the seal that contacts the flywheel that ripped.  The next time the
> break was on the face of the seal (hence the hypothesis that the seal
> had been rubbing on the flywheel  (although it did not appear to stick
> out - the replacement was very well countersunk), of course I don't
yet
> know where it has failed this time.  I do however know from looking
back
> through receipts from the previous owner that this 40k engine has now
> had 6 main seal failures in its life.  My current hypothesis from
> talking to mechanics at VW is that there is something wrong with the
> flywheel (it looked OK but I did not check the diameter of the sealing
> surface) so I have a freshly machined replacement from AVP to replace
it
> with.  Needless to say the O ring was replaced each of the last 2
times
> and I also checked the end play last time which appeared to be well
> within limits (I will measure it again when I dismantle it next
> weekend).
>
> Both the last two times the symptoms have started as soon as the
engine
> was reinstalled.  Oil leaked from arround the bell housing from day
one
> after replacing the oil seal.  Not a huge amount but enough to spot
the
> rear door after freeway driving and leave a daily oil mark on the
> driveway.  This suggests that the seal is under some sort of stress
> right from the start. Then after about 2000 miles the seal fails
> completely and all the oil drains out. I guess if the flywheel
diameter
> was too small it could cause a leak but why the seal then fails
> completely I dont know. I am wondering if there is anything that could
> cause the oil pressure to be too high in this area (faulty instalation
> of bearings??).  Or does anyone have any other ideas - I am at a loss
> now and if it starts to leak again after I replace it this time I will
> have to replace the engine.  Unexpected catastrophic failure of the
oil
> seal is just not something I can live with (it makes me shudder to
think
> of some of the places I have been where this could have happened).
All
> ideas gratefully received!
> David