Date: Wed, 1 Oct 2003 09:55:24 -0700
Reply-To: Keith Hughes <keithahughes@QWEST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Keith Hughes <keithahughes@QWEST.NET>
Subject: Re: vanagon Digest - 30 Sep 2003 to 1 Oct 2003 - Special issue
(#2003-967)
Content-Type: text/plain; charset=us-ascii; format=flowed
Uhmm, Guys...the running of the fan after engine shutoff is just
an artifact of electric fan cooling system. The t-stat has to be
in the radiator instead of the block (which continues to heat
after shutoff, resulting in the fan running for hours - a FUBAR
that happened on a number models when first switching to electric
fans). There's some additional heat conducted to the radiator
which causes the fan to come on long enough to bring it back below
setpoint. The system is designed to accommodate any pressure
buildup after the engine shuts off. Just like the many millions of
cars/trucks made with engine-driven cooling fans.
Keith Hughes
>
> Date: Wed, 1 Oct 2003 07:57:40 -0700
> From: mark drillock <drillock@EARTHLINK.NET>
> Subject: Re: fan switch or sensor, a busdepot question
>
> Gary is right, cooling just the radiator does have an almost
> instantaneous effect on the cooling system pressure. I had a pressure
> gauge and pump on a Vanagon cooling system a few weeks ago trying to
> find a leak. With the engine hot and running at a fast idle the pressure
> in the system would drop by several PSI in a few seconds each time the
> fan started and then slowly climb back up after the fan shut down.
>
> I put the lowest temp switch I could find in one of my Syncros this
> summer but took it out when the fan started running way too much on warm
> days.
>
> Mark
>
>
> Gary hradek wrote:
>
>
>>Mathew, mathew, mathew,
>> yee of so little faith, if I did not know
>>better I would say yeh name is thomas.
>> The after shutdown cooling fan action is about
>>cooling the radiator and coolant in the radiator not
>>the motor. By this air flow, overboiling is
>>prevented. It's the old pv equals nrt equation. If
>>T temperature goes up than pressure and or volume
>>goes up and coolant goes pissing our the back blue cap
>>into the overflow everytime you shut off a hot engine.
>>
>> Which brings me to my busdepot question.
>>Busdepot sells a sensor switch which is a lower
>>temperature switch for the two speed radiator fan.
>>Does anyone know if it works better?
>> thanks gary
>>Date: Mon, 29 Sep 2003 09:30:49 -0700
>>From: Matthew <poll7356@UIDAHO.EDU>
>>Subject: Re: fan switch or sensor
>>
>>yes, but it is stupid. On the a2's the fan will pull
>>air through the
>>radiator and over the engine to cool it. Whereas the
>>vanagon will pull
>>air over the radiator but that air doesn't get over
>>the engine nor does
>>the coolant cycle. What is needed is a small electric
>>pump that will
>>cycle coolant while the after-run coolant fan is on.
>>Unless there is
>>enough thermo-syphoning going on to make it work.
>>Doubt it.
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