Date: Wed, 4 Sep 2013 21:10:07 -0700
Reply-To: Scott Daniel <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel <scottdaniel@TURBOVANS.COM>
Organization: Cosmic Reminders
Subject: Re: nuts vs head gasket job
In-Reply-To: <CAFNeVpFJXXtfyr=wJfCtZk+umDtN00=btEPj7PBRSj1c7UJRTA@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
see below ..
On 9/4/2013 8:45 PM, Tom Carchrae wrote:
> Jim: I guess I got lucky - no coolant drips. But you make a good point
> about what a crazy system that is and why it is prone to failure.
>
> Scott: I have tried a few blue caps. I need to make a cap tester and/or
> run the van with a pressure gauge on the expansion tank when the van is
> running. (Test # 2 from
> http://web.archive.org/web/20050309065156/http://www.bostonengine.com/articles/waterboxes.html
> ).
> I've previously done a test for exhaust gasses, but no CO2 detected. I
> have wanted to plumb a pressure gauge into the cooling system for some time
> now - I am not brave (stupid?) enough to put it in on the dash, but I am
> definitely going to rig up a temporary one to the expansion tank.
>
> When I bought the van, I took it to a mechanic, who said, "hey your cap is
> bad, we changed it" - and he did some work on my heads, what I am not sure
> although it involved valve adjustment to fix low compression. After this,
> the cooling system started blowing up here and there and nearly $2k later I
> was broke and annoyed and have not returned to that mechanic. I then said
> screw this and have most of the work on the van myself since. I drove it
> across western Canada and the cooling system blew up twice more on me -
> after the first time, I changed the cap to another spare I had bought. The
> second time was due to air in the radiator and a giant traffic jam (a
> massive mud slide on Hwy 1) and the van actually overheated (went to ~220oC
> and it was full of water) and the coolant sensor popped off - its
> whereabouts are still unknown. Both times the van was pretty heat soaked
> and running at slow speeds - I learned a lesson there.
>
> So, yeah, it is probably due. And I actually enjoy working on it, so it's
> not all bad.
>
> Btw, are there any engine stands and hoists that are specifically designed
> for working inside your van? :)
IF you mean lowering the engine down to to heads in place..I just use a
floor jack. Can hang it from above too ...like with 2 X 4 and chains.
if it's got this history of cooling system hebbie-geebies and it's not
'basic' like an external leak,
t-stat, or tired radiator ..
if you've eliminated all the normal stuff, take the heads off.
those small green o-rings that keep coolant away from the metal sealing
rings on top of the barrels..
they go south in a few years, easily.
it's an adapted air-cooled design ..it's just funky. It can't work
that well long term, not like conventional all-flat 'real' head gaskets
on normal engines.
I figure head work and head gaskets every 80K miles....every 8 to 10
years max. I would hope you enjoy working on it. It's quite rewarding
to produce a good result.
Scott
>
> Tom
>
>
>
>
>
> On Wed, Sep 4, 2013 at 6:25 PM, Scott Daniel <scottdaniel@turbovans.com>wrote:
>
>> 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
>>>>>
>>>>>
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