Water is a better coolant than most any other liquid because
of its high specific heat; it absorbs a lot of heat energy for
a given increase in its temperature.  Pure water would be the
best coolant, but of course it provides no corrosion
resistance and it would tend to boil at the temperature that
your engine should run at for good efficiency.  When you mix
in antifreeze you sacrifice some of the cooling ability.  This
is why you're seeing a difference in temperature, not because
of a change in circulation rate.
  BTW that IR thermometer from Radio Shack is "a good thing".

Larry A.

---- Original message ----
>Date: Mon, 26 Apr 2004 09:11:59 -0700
>From: gary hradek <hradek@YAHOO.COM>  
>Subject: coolant system trivia  
>To: vanagon@GERRY.VANAGON.COM
>
>I have been dealing with a conditon that I believe to
>be a plugged radiator.   I have ruled out most other
>cheaper fixes.   Over the past week I have isolated
>the radiator at the point of the rear most end of the
>big pipes and plugged them with corks and soaked the
>isolated system with 0.2M citric acid for a week.
>Flushing the system with hot water under house
>pressure gave a flow rate about 6 gallons per second.
>The first flush was very black and showed evidence of
>bits of aluminum from what I am hoping to be some
>after market sealer rather than the radiator itself.
>After flushing the system I filled with the orange
>stuff.   What I find intersting about the vanagon
>coolant system is that the flow rate for water alone
>is much faster than with antifreeze added.   This is
>reflected well by the (temperature at idle as seen by
>the gauge) TAI.
>The TAI with water alone is much lower and at position
>determined by the thermostat.   The low speed fan has
>no problem keeping the engine temperature on the red
>light dot even on a very hot day.   Once you add
>antifreeze the TAI goes up above the light unless you
>increase the rpm.   The TIA on a hot day(about 95)
>will respond more slowly to the cooling affect of the
>low speed fan.
>   My question is would I be better off adding less
>antifreeze and more water and perhaps adding some
>after market corrosion inhibitor and water pump
>lubricant?   thanks gary
>
>
>
>
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