Date:         Mon, 9 Apr 2001 00:12:44 -0500
Reply-To:     Marshall Ruskin <mjruskin@HOME.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marshall Ruskin <mjruskin@HOME.COM>
Subject:      Re: Temperature guage LONG
Content-Type: text/plain; charset="iso-8859-1"

This has to be one of the more interesting questions I have heard recently.

In Canada, we have thermostats that open at a higher temperature because we
are trying to build up a resevoir of heat in the system.

If our thermostats were to open wide at cooler temperatures - the airflow
across our radiators may prevent the engine from ever warming up
completely - and will reduce the efficiency significantly. The system just
cannot maintain adequate residual heat - the rad heat-loss is too great.

Due to this problem, many Canadians have winter covers for our radiators,
that reduce the airflow to 10% or less. This allows the cooling system to
build up a heat store.

Now, it seems to me that the problem in hot climates is exactly reversed.

You would want the thermostat to open at a cooler temperature, because you
want to shed heat at a high rate - and you don't want to build up a lot of
residual heat in the coolant.

The word "RATE" here is the key to this logic.

If the thermostat were to wait, and to open at a higher temperture, the rate
of heat rejection from the cooling system may not be great enough to prevent
eventual overheating.

In other words, "you let the system get too hot, and then the rad can't
catch up".

Therefore, "summer" and "winter" thermostats solve the extreme climate
problem.

Listees, what do you think of this reasoning?

Marshall Ruskin
84 Westy Winnipeg, Manitoba



> I have a question!
>
> What good does a colder thermostat do....except open at a cooler
> temperature and allow the coolant to begin to circulate sooner after a
> cold start. Seems to me that after the engine is warmed to standard
> operating temperature it doesn't matter. Hot is hot.
>
> Can someone explain it to me?
>
> I can see maybe changing something to make to cooling fan come on
> sooner, ie lower temperature, but I don't get the picture as to the
> value of changing the thermostat back by the engine.
>
> If the thermostat is a cold one, if you live in a really cold climate
> like Alaska or Canada or the like, I can see putting in a hotter
> thermostat.It would help the engine maintain temperature in a really
> cold environment.  But even in a hot desert, I see no advantage in a
> cold thermostat. When the engine is up to operating temperature the
> thermostat will go wide open anyway....hot or cold type.
>
> What say the List Guru's??
>
> I really would like to know about this. I have heard about this cold
> thermostat thing always, and it never made sense to me.
>
>
> John Rodgers
> 88 GL Driver
>
> Timothy Hannink wrote:
> >
> > My gauge acts the same way and has since I added RedLine WaterWetter to
the
> > mix last summer. Now it goes above the LED when I sit in traffic idling.
I
> > changed out the radiator fan switch with the lower temperature rated
one,
> > but that had no effect on where the gauge sits or the way it acts.
> > I will be replacing my thermostat with the lower temp one, along with
the
> > housing itself and all of the coolant, so I'll let you know how it goes.
> >
> > Tim Hannink
> > Golidibox - 1987 Wolfsburg Edition Westfalia Camper
> > Winter Park, Florida where it was hot enough today to get the radiator
fan
> > on high speed at a traffic light.
> >
> > ----- Original Message -----
> > From: "Chad" <groch@WORLDCHAT.COM>
> > To: <vanagon@GERRY.VANAGON.COM>
> > Sent: Sunday, April 08, 2001 4:57 PM
> > Subject: Temperature guage
> >
> > > While driving, my temp guage usually stays over the coolant sensor led
but
> > > sometimes it goes just over it (still over the led but higher up).
> > However,
> > > all the time while idling at a stop light the temp guage climbs to the
> > upper
> > > regions. It doesn't go to max but it does go beyond the top of the
led. Is
> > > this normal??????? I know my rad fan works as I've tested it. Could my
> > > thermostat be f'ed up?????? Could it be the thermoswitch in the
rad??????
> > If
> > > so how do I test for it???
> > > thanks,
> > > Chad 85GL