Date: Wed, 1 May 2013 08:24:17 -0700
Reply-To: Tom Carchrae <tom@CARCHRAE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Carchrae <tom@CARCHRAE.NET>
Subject: Re: coolant overflow fears and thoughts
In-Reply-To: <BAY152-ds67116D28AC7C6085DC47AA0B30@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1
Thanks Dennis.
The system is definitely holding pressure and hoses do get firm after it
has been running for a minute.
I'll let the air work out for a bit and then do the bubble check in the
recovery tank (I presume that is the one behind the licence plate). That
makes sense to me; eventually the only thing is pushed out is fluid -
otherwise it must be combustion gasses or boiled coolant gasses, right? It
also makes sense that any air would be pushed out to the recovery tank
first, and replaced with coolant when the system cools.
I do recall reading that is it is normal for the pressurized expansion tank
to not be completely full (ie, has an inch of air in it). Does that imply
that some vaporization of coolant (eg steam) is a normal part of the
system? If so, then I would guess some small amount of air being
purged continuously is normal - but something akin to a volcano
or hookah is not.
Tom
On Tue, Apr 30, 2013 at 4:31 PM, Dennis Haynes <d23haynes57@hotmail.com>wrote:
> Sounds to me you may have a bad cap. Sucking the coolant means there is a
> place for it to go. The cap should hold it in when the revs drop down.
> After a few cycles the internal pressure should equalize and a quick test
> is
> that the hoses become hard, like 12-14 psi hard. If there is air in the
> system it will eventually find its way to the main pressure bottle and then
> work its way out. A final check is to rev the engine and see if you are
> getting a steady stream of air bubbles into the recovery tank. Some is
> normal after a system fill but eventually there should be no bubbles
> visible. If bubbles persist or can be created by throttle-load then you
> have
> a leak most likely from the heads. Loose heads make this extremely load and
> time dependent.
>
> Dennis
>
>
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Tom Carchrae
> Sent: Monday, April 29, 2013 12:55 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: coolant overflow fears and thoughts
>
> > The old hose definitely had holes in it; I tested by partially
> > submersing
> >> it in water. The new hose is airtight - and clear - and I saw how it
> >> sucked fluid up from the overflow tank when the engine started.
> >
> >
> > That last part seems backwards. When the engine is started and is
> > getting warmer, the expansion of the coolant in the system should
> > force liquid or gases, whatever is at the top, out of the pressure tank
> and toward the
> > overflow tank. When the system is cooling down the coolant should be
> > sucked from the overflow tank.
> >
> > Have you tested your pressure cap?
> >
>
> When I rev the engine, the pressure tank always sucks fluid down - the
> reverse when the revs go down (barfing coolant onto the exhaust - mmm).
>
> I agree with what you are saying when the system has heated up, but I had
> just turned on the engine and went to check and, thanks to the clear hose,
> I
> saw it had drawn fluid up.
>
>
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