Date: Wed, 4 Jan 2006 17:25:28 -0800
Reply-To: David Shepherdson <shepherdsond@METRO.DST.OR.US>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Shepherdson <shepherdsond@METRO.DST.OR.US>
Subject: Failed Crankshaft seal yet again
Content-Type: text/plain; charset=US-ASCII
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
>
------------------------------