Tom, if the pressure cap is leaking, then air can enter it just as coolant can escape.   mcneely

---- Tom Carchrae <tom@CARCHRAE.NET> wrote:
> This is not a different issue - this is my cooling issue....  :)
>
> I have a question to ask the experts regarding the bad cap theory.  I get
> how the fluid ends up in the overflow tank - but if it just a cap, where
> does the air/gas come from the displaces the coolant - and why does it not
> pull the coolant back into the pressure tank when it cools?
>
> To Richard; if you replace the cap, and then start having exploding
> hoses/heater cores/plastic connectors/etc - then you are probably in the
> realm of the head gasket/cracked head world.  I believe you can do a quick
> and dirty test of the pressure cap by simply squeezing the coolant hoses
> after the van has been running - are they stiff and inflated, as compared
> to squishy when the van is cool.
>
> Tom
>
>
>
>
> On Mon, Sep 9, 2013 at 4:44 AM, Dennis Haynes <d23haynes57@hotmail.com>wrote:
>
> > Make sure the pressure cap is functioning properly. It has to be able to
> > hold the system under pressure. After that you have the classic symptoms of
> > combustion gasses getting into the cooling system.   The usual causes are
> > loose heads/failed internal gaskets or a cracked head. You need to make
> > sure
> > that coolant isn't leaking back into the cylinders. Even small amounts of
> > coolant getting into the cylinders and then the oil will do damage.
> >
> > Dennis
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> > Richard Golen
> > Sent: Monday, September 09, 2013 7:18 AM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: A Different Coolant Problem
> >
> > Dear List Members,
> >
> > Here's a coolant problem for you to ponder. Recently, on my 87 Westy, after
> > being driven on the highway for an hour or more, the overflow tank gets
> > completely filled. Sometimes, the coolant level is so high that coolant
> > sprays from the vent hole on the top of the tank.
> >
> > The tank slowly goes back to normal level if the van sits for a day or so,
> > or if I let it idle for a while after the engine is cooled down.
> >
> > While driving, the temp gauge is in its normal position. I've also bled the
> > system a couple of times using a "bong".
> >
> > Any ideas as to what could be causing this?
> >
> > Thanks in advance.
> >
> > Ric
> > Sent from my iPad
> >

--
David McNeely