Date:         Sun, 22 Dec 2002 16:22:30 -0500
Reply-To:     Milo's Kitchen <sagmoore@ZOOMINTERNET.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Milo's Kitchen <sagmoore@ZOOMINTERNET.NET>
Subject:      Re: leaking on the pavement, this won't help.
In-Reply-To:  <20021222193216.43400.qmail@web41311.mail.yahoo.com>
Content-Type: text/plain; charset="us-ascii"

Gary,

There are three different seals used to seal the head on the W/B engine. #1)
Metallic "Head Gasket" (a thin flat metal ring) that is compressed by the
combustion chamber outer land in the recess of the head and the top of the
cylinder barrel as a result of the head nut torque. It's purpose is to keep
the combustion gasses (pressure) in the combustion chamber. It is not an
effective coolant seal. In this same area there is, #2) an o'ring in a
groove around the top outer diameter of the cylinder barrel which seals
between the cylinder barrel and the sides of the recess for the barrel in
the head, (the inner coolant seal). This seal prevents coolant from entering
the combustion chamber (see seal #1) and is not dependent on torque but
rather manufacturing tolerances (and a lack of pits!) to do it's job. Seal
#3) is a rather beefy (neoprene? special secret German formula? I don't
know) seal which is U shaped in cross-section and fits with it's "legs" over
the outboard edge of the outer water jacket with it's face against the
corresponding sealing surface of the head (the outer coolant seal). This
seal prevents escape of the coolant to atmosphere (or the driveway).

Among other problems that occur (namely pitting of the head sealing
surfaces), time in service, thermal cycles, nothing lasts forever, etc, both
seal #2 and #3 become less elastic and more brittle. Add to this that after
the initial torqueing, it is very unlikely that this outer coolant seal will
be further compressed to a point that it will do anything good, due to metal
seal #1.

The only reason to attempt to retorque the heads is if for some reason the
head nuts were marginally torqued in the first place (dirty stud threads,
hydro locked head nuts, Gee I'm having a bad day, Rats I dropped the torque
wrench on the floor for the second time today) and the combustion gases
escaping from around seal #1 are pressurizing the cooling system (which if
bad enough can extrude an old seal #3 from it's home, trust me).

Retorqueing the heads on an engine that has been in service for years or
tens of thousands of miles is a stop gap measure, hopefully allowing one
some more time to collect the resources to replace (or pay to have someone
else replace) the offending parts. As Jeff points out, stud failure is a
possibility, (always a possibility I might add), and so the decision to do
this must become a personal and informed one. If you don't elect to do it,
you are faced with tearing the engine apart now, (Merry Christmas everyone)
or feeding it's nasty drinking problem (Ooo, now I'm a co-dependant) till
you can't keep up with it. Just ask my SO.

Sorry for my long dissertation,
Dave

'87 Syncro
'91 Vanagon

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
Of gary hradek
Sent: Sunday, December 22, 2002 2:32 PM
To: vanagon@GERRY.VANAGON.COM
Subject: leaking on the pavement, this won't help.


So Dave?
I do not understand why if it is leaking coolant
retorquing might not help.   In my case it appears to
leak after I shut the engine down?
            thanks gary
leaking on the pavement, this won't help.
HTH
Dave



Date:    Sat, 21 Dec 2002 13:57:27 -0800
From:    Jeffrey Schwaia <jeff@TSSGI.COM>
Subject: Re: Retorgueing Heads

As long as you're prepared for the consequences, I
agree.

-----Original Message-----
From: Vanagon Mailing List
[mailto:vanagon@GERRY.VANAGON.COM]On Behalf
Of Milo's Kitchen
Sent: Friday, December 20, 2002 5:32 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Retorgueing Heads


Not to incur the slings and arrows of angry listers
but, go ahead and
have
the professional mechanic retorque the heads. By it's
very definition,
Retorgueing means (in this isolated case) draining the
coolant, backing
off
the head nut (one at a time in proper order) and
bringing them back up
to
proper torque. If a stud is going to break, most
likely it will break
anyway. Just don't have at it and try bringing up the
torque from its
corroded in place state. Okay I'll admit it, after
replacing two heads
and
suffering the classic "huffing coolant from the
recovery tank" symptoms
after about 600 miles, I retorqued my heads to 40 (!)
foot-pounds,
(hey,
I'll have to take the SOBs off again anyway so why
not? calibrated T/W
BTW),
and no more problems of that sort. If the coolant
system is being
pressurized by combustion gas, it will either work, or
it won't. If
it's
leaking on the pavement, this won't help.
HTH
Dave


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