Date: Thu, 18 Feb 2016 10:42:52 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Expansion tank under pressure when cold?
In-Reply-To: <CAE_mVa2Q1vEdd44zSmbvordB1UqqbG-vW7cnaGJ3p99aPn60Rg@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Having the heads leak from the rubber coolant jacket gasket or internally from the top of the cylinders is not related. Two separate failures. Having the heads properly clamped to the top of the cylinders is critical sine the top gaskets are really not compressible. The outer gaskets are compressible from new and overtime they lose their ability to maintain a seal during various engine temperatures due to expansion-contraction of that gasket. You will never fix an outer gasket leak by re-torqueing the heads. There is a chance of fixing the inner gasket leaks by re-torqueing. However, if the heads are lose you have to ask why. If incorrectly torqued during installation you are lucky. If not either and overheating event occurred and the studs are over stretched or they are failing. There is a chance that during re-torqueing some studs may not hold torque and they can keep stretching or break. Once one breaks you are looking at head and probably cylinder removal and if one breaks near the base you are looking at a full tear down and a visit to machine shop with a milling machine to get that piece out for you.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Michael McSwain
Sent: Wednesday, February 17, 2016 1:14 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Expansion tank under pressure when cold?
Any easy way to test for combustion gasses getting into the coolant?
Loose or cracked heads would produce a leak or weeping from the head area I assume?
Radiator should be easy enough to check for leaks, but heater core not so much.
I've tried taking the expansion tank cap off after letting the van sit overnight and it still overflows when removed. Where I park it is slightly inclined with the front end up, but not much. I'll try parking it front down tonight and try removing it again tomorrow morning.
Is applying 10 or so psi of pressure to the expansion tank and looking for pressure drop and leaks a bad idea?
On Wed, Feb 17, 2016 at 1:01 PM, Dan N <dn92610@gmail.com> wrote:
> I think it depends on how long you let the engine rest after you shut
> it down. There always some residual pressure in the cooling system and
> it will come near zero if you wait long enough... I let it sit
> overnight. My mechanic revs the engine up to bring the level down, add
> the coolant and put on the cap presto..
>
--
m.
