Date: Thu, 5 Sep 2013 22:11:24 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: nuts vs head gasket job
In-Reply-To: <CAFNeVpErfRPByb5wsGeTwS606_O_u0tFRN+NYJ+LPy_bxptp0g@mail.gmail.com>
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At some point VW changed the head torque spec to 41 ft lb. In fact there was
a recall to re-tighten the heads I think back in 89. I had my Syncro since
new and had them do that tightening.
Getting the intake manifolds out of the way to get to those two center bolts
on top is not that bad. Cut or loosen the clamps on the intake hoses, remove
the two blots and lift the end, injectors and all.
Since this is part diagnostic and part being lucky, just check the torque
first. You want to use a beam or dial indicator type torque wrench, not a
clicker type here. If the head nuts are lose you need to be concerned.
Unless you know they were not properly installed you have to reason that the
studs were stretched, usually from overheating. If only one or two stretched
you have to consider erosion damage. They just might snap. Now the head has
to come off and the cylinders have to come out. If the stud breaks near the
case you will be looking at a full teardown and some machine shop magic.
Your symptoms can also be caused by a cracked head.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Tom Carchrae
Sent: Wednesday, September 4, 2013 12:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: nuts vs head gasket job
I've put this off long enough. I got a few trips from my van this summer,
but on the last day I drove it, it backed up the coolant in the reservoir
(behind licence plate) three times in one day. I would pull over when the
blinking low-coolant light turned on, drain the coolant out into a bottle,
start the vehicle, open the hot pressurized tank, and pour the coolant back
where it belonged.
Yesterday I took the valve covers off and used a torque wrench to inspect
the tightness of the nuts on the heads - well, all the easy to get to nuts
(so all but the two behind the air intake - I have only removed the air
filter box so far).
I have only done one side so far, but I found one of the bolts in the centre
of the head to be slightly under spec (37lb). I recall Dennis Hayes saying
(email below) that this managed to solve head gasket symptoms 50% of the
time if done soon enough. I doubt I have been soon enough, but how does one
tell.
I am prepared to do the head removal but boy would I be happy if it was as
simple as tightening some nuts. Would I be overly hopeful to think that
this minimal nut tightening this late would save me having to remove the
heads?
Tom
84 Vanagon
On Thu, May 9, 2013 at 2:19 PM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:
> One problem with relying on the sniffer tests is that they are looking
> for un-burned hydrocarbons. In order for this to work in addition to
> the leak you also need a combustion failure in the leaking cylinder.
> While cracked or loose heads may also cause a combustion issue you are
> in deep trouble by the point the sniffer tests pick it up. Keep in
> mind if those gasses can get out in some cases coolant can get into
> the cylinders. Antifreeze into the cylinders and then into the oil can
> cause some real damage. Long before antifreeze in the oil is visible
> the stuff becomes extremely corrosive and can quickly destroy bearings
> along with crank and cam surfaces. It can also destroy pistons by
> blowing out the tops and destroying the ring lands.
>
> If the engine has ever been overheated, (even before a rebuild) or has
> had the heads off for any reason loose heads can be the cause. I
> probably have a better than 50-50 success rate in fixing these issues
> just be retourqing the heads if the problem has not been left so long
> that the head seals (inners) or the tops of the cylinders have burned
> or pitted away.
>
> Dennis
>
