Date: Mon, 7 Apr 2014 20:11:01 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: The Head is Off, Assume Cracked?
In-Reply-To: <CAAymtAbnq8k6W7fXUc1WFOq3gADRjhZHg9N6TzfxBKLKy-+SEg@mail.gmail.com>
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Here is the poor man's method of finding head cracks.
Get some cans of brake cleaner, preferably nonflammable and non-foaming.
With plug in place set up head with combustion chamber facing up. Fill each
chamber with the brake cleaner. It should hold it. Leaky valves will be
evident. If the cleaner goes into the coolant chamber test is done.
Then for the valves that hold, turn the head so the intake ports face up.
Fill the ports. Anything that leaks without going past a valve is a problem.
Then stand the head up and test each exhaust port.
I have seen heads crack in all sorts of ways. I had one van where both heads
cracked right across the top from an outer head nut hole through both spark
plug holes right to the opposite side. A good cleaning will also help find
these. A local machine shop can tank clean the heads for a few bucks. But if
you fail the first tests then you are done anyway.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Paul Smith
Sent: Monday, April 7, 2014 10:45 AM
To: vanagon@GERRY.VANAGON.COM
Subject: The Head is Off, Assume Cracked?
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
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