When I had a plugged breather hose, the pressure came out the dipstick
tube, pushing the dipstick out an inch or so.  I believe this is the
normal route for excess crankcase pressure.

Karl Wolz

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
Behalf Of
> John Rodgers
> Sent: Wednesday, January 04, 2006 7:47 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Failed Crankshaft seal yet again
>
> David,
>
> I doubt seriously that crankcase pressure is blowing that seal. I had
a
> pison burn a hole right through it. All the pressure of combustion
then
> blew right into the crankcase. Talk about crankcase pressure -- but my
> engine didn't blow that seal. Instead, the pressure moved through the
> crankcase, then to the pushrod tubes the to the rocker covers, there
it
> blew out  the rocker cover seals. And it did that not once but twice
> before I realized I had a hole in a piston. The cranskshaft seal is a
> much tighter seal that the rocker cover gasket, and so the rocker
> gasket  blew instead. So I really don't see that crankcase pressure
> would ever blow the seal. It will most likely blow something else that
> is not seated as tightly as that seal is seated.
>
> Regards,
>
> John Rodgers
> 88 GL Driver
>
> David Shepherdson wrote:
>
> >Thanks to all that gave me feedback on this problem. One suggestion
was
> >excessive crankcase pressure, I am pretty sure that the breather hose
> >(to the intake boot) is OK but will certainly double check (and try
> >putting my hand over the oil filler pipe when I get it running to see
if
> >I can feel it). Another was endplay/endfloat but as I said in my
> >original e-mail I did measure that and it seemed to be OK. I don't
know
> >about the thrust bearing but I am not sure how I can check this (and
if
> >it means engine disassembly then that pretty much equals a new engine
as
> >far as I can see).  I guess it could be a engine case fault (the
engine
> >was rebuilt by VW Canada) but I am not sure how to check that (and it
> >would necessitate a new engine anyway).  The e-mail below by Ratjen
is
> >certainly food for thought.  I have seen a very thin wear line which
> >appears to be straight (I do not believe that the wear line is
causing
> >the problems as the "new" flywheel is the same and it has just been
> >machined and inspected) but I will check again.  I have heard sounds
> >that could be a bearing going but then again I think it might be my
> >paranoid imagination because it does not seem to have got worse (and
> >sometimes is not there at all).  Anyway, I don't think the bearing
can
> >have been bad through all 6 or 7 oil seals which go back 20k miles or
> >so. I am trying to think of ways that I might measure crank or
flywheel
> >wobble (the engine runs smooth enough - any ideas?).  Maybe putting
the
> >new flywheel on will cure it.  By the way Ratjen asks what I mean by
> >catastrophic failure?  I mean that all the oil drains out in a couple
of
> >seconds while the engine is running and of course the oil warning
buzzer
> >comes on. This is caused by actual damage to the seal (the sealing
lip
> >which contacts the flywheel was torn the first time and the face of
the
> >seal that faces the flywheel had a small crack in it the second
time).
> >I can't be sure that this is what happened the times before I bought
it,
> >it could be just that the seal was dripping oil. Judging by the speed
at
> >which the oil came out this time I am pretty sure that the seal is
> >damaged again for the third time, it will be interesting to see
where.
> >Could this kind of seal damage occur as a result of crank or flywheel
> >wobble or case mis-alignment(I can see how that might cause leaks but
it
> >is not so obvious why that would damage the seal). I can also rule
out
> >pilot bearing as I changed this last time it happened.  Still looking
> >for ideas (and potential solutions)!!!
> >
> >My list so far looks like this:
> >Check crank breather hoses
> >Measure endfloat before removing flywheel
> >Also try to measure if flywheel is running true
> >remove flywheel and note and photograph damage to seal
> >Check with straight edge that it is not protruding from the case
> >Remove seal and check condition of thrust washers
> >Try to measure crank wobble (?)
> >Try to determine if case is symetrical
> >Check sealing surface of flywheel for wear marks and investigate for
> >straightness and continuity
> >Try to check end of crankshaft for trueness
> >Install new fly wheel and check endfloat and adjust if neccessary
> >Remove and install new felt washer, O ring and oil seal
> >Install and torque flywheel
> >Check flywheel trueness again (??)
> >anything else??
> >
> >Thanks,
> >David
> >
> >
> >------------------------------
> >
> >Date:    Tue, 3 Jan 2006 12:18:13 -0800
> >From:    =?iso-8859-1?Q?Bj=F6rn?= Ratjen <Bjorn@IGLIDE.NET>
> >Subject: Re: Failed Crankshaft seal yet again
> >
> >David,
> >
> >As I know how frustrating these things can be let=20
> >me wade in with some comments. The seals are made=20
> >to keep oil from wandering along a smooth and=20
> >perfectly round surface. They need to stay in=20
> >place and follow the moving surface in an=20
> >absolutely straight path. If the matching surface=20
> >is either not completely round or wobbles then=20
> >the seal will break. You can look at the surface=20
> >of the moving part. Is there one (or two matching=20
> >the lips of the seal) straight line?=3Dgood. Does=20
> >the line have differing thickness or is it not=20
> >completely straight?=3Dbad. Wobble can occur=20
> >through deformation of the moving part,=20
> >misalignment of mounting surfaces (crankshaft to=20
> >flywheel) or excessive play in bearings. Look=20
> >also for evidence of movement of the seal in the engine block.
> >
> >When the seal is installed it needs to be tight=20
> >and straight in the engine block. Only press on=20
> >the outer ring for installation. Check for any=20
> >rough parts or burrs in the moving part which=20
> >could damage the seal during installation. The=20
> >seal actually creates a small indentation in the=20
> >moving part over time. Check this indentation=20
> >carefully for any tiny imperfections and measure against seal if
> >necessary.
> >
> >Also check pilot bearing for transmission shaft=20
> >(in flywheel) as too much play can damage transmission seal and oil
> >clutch.
> >
> >I do not know what you mean by "catastrophic"=20
> >failure. A small leak can drain a lot of oil. I=20
> >remember when I spent a day to help a friend to=20
> >replace his aircooled van engine (at a parking=20
> >lot) with another one a friend of his had stored,=20
> >only to find that all the oil drained within=20
> >50kms because the crankshaft seal had simply=20
> >dried up. We bought a tow bar and I towed him=20
> >300kms on the German Autobahn with my VW van=20
> >through the night. As he had a 1600cc engine and=20
> >I had the new! 2000cc engine he found it to be=20
> >almost as fast if he had driven on his own power. :-)
> >
> >Hope this helps.
> >
> >Bj=F6rn
> >
> >At 06:25 AM 03/01/2006, you wrote:
> >
> >
> >
> >>Date:    Mon, 2 Jan 2006 23:47:14 -0800
> >>From:    David Shepherdson <shepherdsond@METRO.DST.OR.US>
> >>
> >>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
> >>
> >>
> >>
> >
> >------------------------------
> >
> >
> >
> >