Date: Mon, 7 Apr 2014 10:45:20 -0400
Reply-To: Paul Smith <paulwithwesty@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Paul Smith <paulwithwesty@GMAIL.COM>
Subject: The Head is Off, Assume Cracked?
Content-Type: text/plain; charset=ISO-8859-1
This thread really started about a week ago, as detailed in my post on
March 30th: "Replacing the Head Gaskets (Maybe the Head)?" - so I won't
repeat it all here. The vehicle is an 1989 Westy, 2.1 WBX, started with
white smoke a few minutes after startup, returned to the driveway and later
when I pulled the spark plugs I found coolant in the passenger side front
cylinder.. I did manage to get the passenger side head off, going slowly
and carefully and with the expected pain points (exhaust system, etc.). The
problem cylinder was the front cylinder and it was stuck firmly to the
head, requiring use of the methods noted in Bentley and on this list to
finally free it. The sealing o-ring at the top of the front cylinder looked
damaged (or deteriorated) compared to the same o-ring on the rear cylinder,
which appeared to be in good shape. I thought I might have a cause, except
that the compression gaskets in the head both looked good, no apparent
damage or discoloration. I have no evidence that the coolant system was
being pressurized by exhaust gases, only somehow coolant was entering the
front cylinder. I don't see any cracks in the cylinder head combustion area
(hairline or larger), although I have not cleaned all the carbon deposits
off. Both exhaust ports look about as expected, fine coating of black
carbon, with the front port slightly "damper" or more oily. The intake
ports revealed an oddity. The rear (good) intake port looked about as
expected, clean metal with a light oily sheen. The front (bad) cylinder
intake had a coating of grey slimy stuff covering a good part of the back
curve of the intake passage and up around the valve guide area. I was
wiping it out without thinking how odd it was (long day) when I stopped. It
seems unlikely that coolant would be blown up into the intake from the
cylinder (valve is primarily open on the downstroke), but coolant leaking
into the intake passage would certainly be sucked into the cylinder. If it
were being sprayed in from crack in the head it might also form a coating
on the hot intake passage walls. I guessing that this may have been
developing over time, as Dennis Haynes mentioned. I took a close look at
the piston tops - the rear had a light coating of combustion/carbon
deposits; the front piston had some, but is fairly clean (steamed clean?)
in the center portion. The cylinder walls look good in both, smooth,
unscored and not scorched or discolored.
Has anyone experienced a crack like this in the head into an intake
passage? I can't see anything obvious, but without removing the valve and
getting a good view angle I might not. Still might not find anything
visually in any case. I tried briefly to block all the coolant passages and
apply pressure to detect a leak - couldn't get a good seal. All this is
being done in my driveway, no garage, so my shop facilities are limited. I
can't understand how a grey coating could be formed in the front cylinder
head intake passage without a leak of some kind, along with the clear entry
of coolant into the cylinder. Both intake tubes upstream of the head seem
fine (the same). The driver side intakes are also fine.
It seems like a replacement head may be the best option at this point. I'm
not sure I can find the cause, although it pretty clearly appears to be in
the head. I would rather install a new head than try any partial repair or
patch. Then if I get curious enough I can pull apart the bad head and see
what I find.
Thoughts?
Thanks,
Paul
|