Date:         Mon, 11 Jun 2007 09:00:51 -0700
Reply-To:     Mark Drillock <drillock@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Drillock <drillock@EARTHLINK.NET>
Subject:      Re: coolant leak after long idle
Comments: To: Malcolm Stebbins <mwstebbins@YAHOO.COM>
In-Reply-To:  <673226.14842.qm@web43144.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=us-ascii; format=flowed

Nice old post with good info. The behavior of the thermostat as regards
coolant pressure in the radiator is well known and not a matter of
belief or faith. The thermostat is on the radiator return line, where
that line rejoins the engine. The water pump can thus push coolant to
the radiator even if the thermostat is closed, as long as the radiator
bleed screw is open. Reving the engine slightly helps overcome the fact
that the radiator top is higher than the pump. The coolant will "spill
over the top" inside the radiator and fill the return pipe as well since
coolant is heavier than air. The air will rise to the higher point,
namely the bleed hole, and after coolant mostly fills the pipes and
radiator it will start to spill out of the radiator bleed hole even with
a closed thermostat.

I agree that the system can be bled just fine without raising the front.
It can even be done with the rear raised and that is how I mostly do it.
I don't raise the rear just for the bleeding but many times I already
have the rear raised for some repair or replacement that requires
bleeding to complete.

Mark

Malcolm Stebbins wrote:

> --- David Etter <detter@MAIL.AURACOM.COM> wrote:
>
>
>>I'm sure others will jump in with a more detailed check list,
>
>
> As Dave suggests, here is my post on the topic.  I differ from what Dave said in that I do believe
> that the engine/coolant must be hot/warm for the thermostat to open to pressurize the radiator to
> force the air out.
>
> The actual bleeding part is near the bottom of this post:
>
> http://gerry.vanagon.com/cgi-bin/wa.exe?A2=ind0203C&L=vanagon&P=R28247   m2cw
>
>
>
>