Date:         Sun, 3 Feb 2002 20:45:52 -0800
Reply-To:     Leon Korkin <korkwood@WSHOST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Leon Korkin <korkwood@WSHOST.NET>
Subject:      Re: Coolant pressure gauge mounting
In-Reply-To:  <17b.310ace2.298f5cc4@aol.com>
Content-Type: text/plain; charset="US-ASCII"

Saw this thread and wanted to add my .002 worth.
Vanagon cooling system is an afterthought added to watercooled aircooled engine.
Expansion tank location helps in keeping air bubbles and filler tank is a
band-aid in case there is too much air inside system .
 Too many connections to leak, poor quality parts.
All this mess could be avoided if VW used engineers, not salesmen
as designers. There is enough room to put front fill radiator with fill tank
in front where it belongs. VW never fixed that problem...
I second that there are pressure drops across flow restictors resulting in
diffrent pressure readings in diffrent spots. Would have been better to
keep the same main tubing ID thruout system for more consistent flow and cooling
Leon
85 Subwagen Westy


2/3/02 7:40:52 PM, Frank Grunthaner <FrankGRUN@AOL.COM> wrote:

>In a message dated 2/3/02 6:47:06 PM, hilltech@NETINS.NET writes:
>
><< In a closed hydraulic system, such as the cooling system in our
>Vanagons, the pressure everywhere in the system is very, very, nearly
>equal.   >>
>
>A note of disagreement here. As I just indicated in a reply to the question
>posted, there is a difference in magnitude of signal (pressure change) and
>rate of response. As indicated in Chuck Hill's response, the pressure should
>be constant in a closed hydraulic system ... except for compliant systems
>(hoses), pressure drops (across radiator, small channel tubing) and flow
>restrictors (heater circuit).
>
>As I was searching for the right location, I tested three areas ('82 Diesel
>Vanagon configuration), to wit the coolant reservoir tank, the radiator bleed
>valve and the heater inlet line just before the flow control valve. As I
>recall (age damaged neurons and the general passage of several years since
>the event). The heater line response was poor and sluggish, and only behaved
>intelligently when the flow valve was open. All the same high pressure
>responses were seen on the radiator tap, but they were muted (several psi
>less than the recovery tank. Never did see the 1 to 2 inch negative pressure
>at the radiator over night.
>
>Remember, the system shows many transient phenomena. The pressure at the
>water pump inlet is lower than the pressure at the outlet. Etc, etc.
>
>I'm tired! A pressure gauge anywhere is good. Far better than none. If you
>are disturbed by rapid gauge movements (thinking that they distract you from
>the formidable process of driving) then mount it in the heater loop. If you
>enjoy the excitement and thrills of rapid gauge response mount it in the
>coolant reservoir. If you want to diagnose the state of the cooling system
>instead of concentrating on SWMBO's latest diatribe about attention paid to
>oncoming traffic, mount three! Than is, one in the reservoir, one on the
>radiator bleed screw and a differential one to monitor the real time
>differences in front to back pressure.
>
>Frank Grunthaner
>
>