Date: Fri, 27 Mar 2009 15:06:59 -0500
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: diagnosis--blown piston ring?
In-Reply-To: <485c3ee60903271200n376f4a18l314d740e940bd4c0@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
This sounds exactly like what happened to my 88 GL once
While cruising back from Albuquerque to OK City a few years ago -- just
west of Clinton OK on a Sat. night - I was startled by this loud "POW!".
I checked the the rear view mirror, saw an approaching 18 wheeler and
saw smoke boiling between me and him. I instantly checked all the
instruments and everything was OK so far as the idiot lights were
concerned and temperatures. . I pulled off of I-40 at the next ramp -
which happened to be just ahead - and into an all night truck stop.
There was only a night attendant there, but we looked together and there
was oil everywhere. Back of the van was covered, engine was covered and
it was dripping all over. Oil was off the dip stick. There was not good
light, but we filled it up with oil, started the engine, and instantly
oil was pouring out from somewhere. I was done for the night.
As I was between Somewhere OK, and Nowhere, OK I called for a roll-back
and got the van delivered to Clinton, OK, which was the next town going
east. Being as it was Sat. night and next day was Sunday, I had the van
dropped at the local Holiday Inn and stayed over until Monday. On Monday
I got the van moved to a Garage where they checked it out. Checked the
oil, fired up the engine, oil started running out from under the valve
cover gasket. Stuck a new gasket in, fired it up, In less than a minute
there was a loud POW! and oil came pouring out from the valve cover.
Next came a compression check. Three wee 150 psi, and the fourth was
flat - "0" compression. With the engine cold, the mechanic turned the
dead cylinder to TDC so both intake and exhaust valves were closed. The
mechanic did a static differential compression check and you could hear
the air coming out at the valve cover gasket and oil burbling at the
same point. Diagnosis? Most likely a piston with a hole through it
allowing gases nto the crankcase and out through the pushrod housings
into the rocker box cover where ti blew out the seal, thus the oil all over.
I rented a truck and auto trailer and trailered it all the way back to
Birmingham. AL, which had been my destination all along.
I knew an old time VW mechanic so I took it to him. He pulled the
engine, tore it down, and there it was - a piston with a hold burned
through. A portion of the top, the corner and the sided of the piston
had melted and a hole had blown through the hot metal. The cylinder was
destroyed, but there was no head damage. Now if you have not seen a
piston that has burned, then you have missed something. That experience
will tell you a lot about your engine, and these engines.particularly.
First off, I learned that the number 2 cylinder is particularly
vulnerable to over heating. Second, I learned that a piston that burns
is going to put metal particles completely through your engine, and only
a complete tear down and washout will ensure all the metal particles are
out of there. If you do not do that, and a little piece of metal gets
moved into an oil gallery or some other critical place, your 2.1L WBX is
going to have a massive coronary - as in throw a rod most likely.
After an event such as burning out a piston to the point there is
blow-through into the crankcase, I don't think I would want to do just a
top end rebuild, especially if there were a lot of miles on the engine.
Yours sounds like a piston with a hole in it. You decide what to do
about it.
Good luck,
Regards,
John Rodgers
88 GL Driver
Ben S wrote:
> i was driving my 86 2.1L westy up to tahoe sunday night when i noticed
> oil on my rear window. pulled over and saw that at least a quart of
> oil had been blown out of the dipstick tube. engine was clearly
> running on 3 cylinders. i added oil and limped back home. last night
> i did a compression test. 150 psi in the cylinders that were firing,
> 0 psi in the one that was not.
>
> could this be anything other than a piston ring failure? is it normal
> for them to fail so catastrophically? engine has about 180k on the
> clock and everything looked normal in an oil analysis done about 2k
> miles ago. valve springs seem ok from visual inspection (is that
> enough?). is there anything else worth checking?
>
> how likely is it that i scored the cylinder wall or did other damage
> to the engine during my 30 mile drive home? will i further reduce the
> "rebuildability" of this engine if i continue occasionally driving
> (have to move the van twice a week to avoid parking tickets)? should
> i pull the spark plug and/or fuel injector power for that cylinder?
>
> the body on my van is pretty rusty and shot, so i'm not sure it's
> worth the effort and expense to install a new engine... how feasable
> is it to rebuild one in place? could i just throw in new bearings,
> piston rings and head gasket? or maybe just replace the one that blew?
> or is it likely that the cylinder is all tore up and needs to be
> bored?
>
> i'm planning to leave the country in the next year, so i really only
> need to get another dozen or so road trips out of my van before she
> retires... she's not used daily.
>
>
>
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