PS to my last post.
Make sure it's not the blue pressure cap. Try another one. They are
notoriously flakey sometimes.

On 9/4/2013 4:37 PM, Jim Felder wrote:
> The head bolts and the heads do two things simultaneously, and do only one
> of them very well.
>
> They hold the aluminum ring that serves as a true head gasket; that is,
> that gasket confines the compression gases to within the cylinder, without
> leaking it to the outside world. The other thing that is going on is that
> the head also squeezes a rubber gasket between the head and the water
> jacket on the block. This is imprecise. Normally, the compression head
> gaskets do not fail very often. That is not true of the outer water gasket
> which is held in place by the same head bolts. Think of it s a circle
> (actually two circles on each side) of metal, with very precise clamping
> pressure to hold in the combustion gasses, surrounded by a rubber gasket
> which deteriorates, holding in the coolant.
>
> Guess which is going to go first?
>
> Yep, the rubber. If your head bolts are tight enough to contain the
> combustion gasses, but you are leaking water, you are not going to affect
> the rubber more than a thousandths or two by tightening the already tight
> bolts holding the compression gaskets in place. If you are leaking coolant,
> it is because your rubber gaskets have a breech somewhere, not because
> there is not enough pressure on them.
>
> It always makes me feel better to go through the procedure or tightening
> the bolts as you suggest, but, in the end, you will have to pull the heads
> and replace the outer rubber gaskets.
>
> Jim
>
>
> On Wed, Sep 4, 2013 at 11:54 AM, Tom Carchrae <tom@carchrae.net> wrote:
>
>> 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
>>>