Date: Mon, 8 Mar 2004 06:20:03 -0500
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: cooling system design
In-Reply-To: <Pine.SOL.4.58.0403080354260.28084@rygar.gpcc.itd.umich.edu>
Content-type: text/plain; charset=US-ASCII
The major difference is the capacity of the cooling system. The golf has
less than 2 gallons of coolant where the vanagon carries almost 5. The
main expansion tank is not large enough to allow for this without
becoming air bound when cold and overflowing when hot so the second tank
is needed. The second tank being downstream of the relief valve allows
adding make up coolant without opening the system. Many cars are set up
this way. Another advantage is that without air in the pressurized
system, the coolant is less likely to carry entrained air/O2 which
avoids cavitation, internal pitting and corrosion.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Jonathan Farrugia
Sent: Monday, March 08, 2004 4:05 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: cooling system design
okay i understand that, thats basically a description of how the vanagon
cooling system operates. what i was trying to get at in my first post
which re-reading it i see i didn't convey. is that the golf system
doesn't have the second over fill tank it only has one expansion tank
with air in it. the golf tank has two hoses attached one that routes to
the water pump allowing the water pump to draw from the expansion tank,
and another small hose about 5/16" that routes coolant form the top of
the radiator into the expansion tank. under operational conditions the
small 5/16" hose provides a steady stream of coolant from the top of the
radiator to the expansion tank. upon cool down the golf system draws
atmospheric air into the expansion tank if i needs to balance the vacuum
on the cooling system.
what i want to know is what are the technical differences between these
systems, i.e. contrast comparison of the systems.
jonathan
On Mon, 8 Mar 2004, Daniel L. Katz wrote:
> as the engine cools the pressure drops in the expansion tank and
coolant
> is pushed up to the expansion tank from the overflow tank, which is
always
> at atmospheric pressure. air buoyed up on top of coolant in the
expansion
> tank reduces this pressure drop, but this air tends to get pushed out
when
> hot, expanding coolant flows out toward the overflow tank.
>
> dlk
>
> On Mon, 8 Mar 2004 01:47:38 -0500, Jonathan Farrugia
<jfarrugi@UMICH.EDU>
> wrote:
>
> >i am interested in having a discussion about different types of
cooling
> >systems. specifically the design benefits and difference between the
> >types of cooling systems in other vw's and the type of cooling system
in
> >the vanagon. for point comparison we could use the 85-92 golf. that
> >system has a expansion bottle with air in it, the air is at the
highest
> >point in the system and it the system operates fine. where as in our
> >vanagons we have a completely filled system with no air. what is the
> >technical problem with having a little air at the highest point in
the
> >system or in an expansion bottle.
> >
> >if there is a technical name for systems with air and systems without
air
> >i would be interested in what they are called.
> >
> >jonathan
>
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