Date:         Mon, 7 Sep 2015 10:06:46 -0600
Reply-To:     Steve Williams <steve@WILLIAMSITCONSULTING.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Steve Williams <steve@WILLIAMSITCONSULTING.COM>
Subject:      Where is temperature sensor & why does needle drop when heater is
              on?
Content-Type: text/plain; charset=utf-8; format=flowed

Hi,

Driving my 1991 Westfalia, I see a phenomem that I do not understand.

When my van is up to temperature, the needle sits approximately where
everyone describes, just below the LED.

On a cool day (around freezing yesterday), if I turn on the front
heater, the temperature guage goes down.

This, I do not understand.  I would have thought the front heater would
not affect the temperature of the water exiting the engine coolant
jacket that significantly.

As I type this email, I originally thought that the thermostat would
start restricting coolant flow to the to the front radiator as the
temperature lowered... but I imagine that it's not cooling off
sufficiently for that to happen, since I think these vehicles have
around a 185 degree thermostat & the coolant must be much hotter than
that.  On that note, what temperature range would the coolant be running
at when the engine is "up to temperature".  I'm considering getting an
Infrared Temperature gun as a new shop tool.

Does the behavior I describe above make sense, the front heater causing
the needle on the temperature guage to be a bit lower (about 1/2 a
needle width)?

Also, what would make a van run a bit cooler?  On some cooler days, it
seems the needle can't quite make it up to the "normal" summer time
location even without running the heater.

I don't drive that much in the fall, mostly summer time & don't use the
heater, so don't really have a baseline comparsion to work with.

Thanks,
Steve Williams