Date:         Wed, 5 Sep 2001 08:22:16 -0700
Reply-To:     Bill Kasper <dragonlist@IPMTS.UCSC.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Bill Kasper <dragonlist@IPMTS.UCSC.EDU>
Subject:      Re: VDO Gauge Guru - temp vs voltage???
Comments: To: David Marshall <vanagon@VOLKSWAGEN.ORG>
In-Reply-To:  <AIEFIGCNNANNIHLNFBPEGECEDOAA.vanagon@volkswagen.org>
Content-type: text/plain; charset="US-ASCII"

on 9/4/2001 10:40 PM, David Marshall at vanagon@VOLKSWAGEN.ORG wrote:

> In my former 1984 Westfalia I would be hard pressed to get the oil above
> 105C and usually it would be about 95C - this is with a 1.8L engine.  My
> Syncro goes up to 120C and this is with a 2.0L engine.  Originally I thought
> it was displacement differences, but now I know this is not the case.  My 84
> Westfalia would be +- 0.1V 14.4V while driving down the highway and the
> voltage would not change more than 0.2V with the lights on.  My 1988 Syncro,
> along with a friend's 88 Syncro both drive at around 13V and the voltage
> fluctuates with the electrical accessories that are turned on.  With high
> beams on I am close to 11.5V.  Now, we both notice that the lower the
> voltage goes in the system the higher the oil temps got - instantly - if you
> turned on the lights would add about 5 degrees the instant you turn on the
> lights.  Now today for the experiment, I took a 1.5V dry cell and installed
> in in series with the positive lead of my gauge and the reading went no
> higher than 105C when I pushed the engine really hard.  So... after all of
> this I have some questions:
>
> - What voltage are these gauges supposed to run at?
> - Does anyone have a resistance to temp graph?  The one in the Bentley
> manuals for the water temp is wrong when it comes to oil temps.
> - What is wrong with our Syncro electrical systems that it can't hold 14.4V?
> I even tried the same alternator in both vans and the problem stayed with
> the Syncro...


david, that's very interesting.  my alternator went bad on our trip, and i
had a good used one installed with new brushes...the adjustable voltage
type.  the mechanic set the voltage at the battery to 14.7-14.8 so the drop
with items on wouldn't drop it below about 14 (so he says; we tried the
lights and powering a window and it went to about 14.4-14.5; putting the
fridge on later while driving wasn't a problem, but i don't know the
numbers).

let us all know what you find out?

bill
'87 syncro westfalia
http://www.scruznet.com/~kasper/pics/westy/