Date: Wed, 16 Jul 2003 13:20:58 -0700
Reply-To: gary hradek <hradek@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: gary hradek <hradek@YAHOO.COM>
Subject: Re: 2.1L coolant light problem
In-Reply-To: <20030716153611.L12473@gull.us>
Content-Type: text/plain; charset=us-ascii
David,
My disconnect is more obvious. Sometimes it
will run 10 or 15 minutes in the hotter area with only
the low speed fan running. Othertimes the medium
speed fan will be running when the temp gauge
indicates that it should be off. I think it is just
a poorly designed system that works marginally. I
think the actual coolant flow maybe variable and is
the cause of the problem. This is a tuff thing to
measure but it would explain the temperature
variations with a constant engine speed.
gary
--- David Brodbeck <gull@gull.us> wrote:
> On Wed, 16 Jul 2003, gary hradek wrote:
>
> > I have always observed that there is a bit of a
> > disconnect between what you see as an engine
> > temperature(the light) and what the fan in the
> front
> > is doing(sensor system with three speed fan). I
> > suspect the temperature sensor for the fan is
> poorly
> > placed.
>
> It's placed halfway through the radiator. That's an
> odd but reasonable
> spot.
>
> I've noticed that the fan and the engine temp are
> often "out of phase",
> because the fan is monitoring the radiator temp, not
> the engine temp.
> What I mean is the engine temp will start to climb,
> and a minute or two
> later the fan will switch on. The engine temp will
> drop, and a minute or
> two later the fan will switch off. In a long
> stretch of stop and go
> traffic it can almost look like the fan is running
> mostly at the low
> points in the engine temperature. I figure this is
> because of that long
> coolant loop between the temperature you're looking
> at, and the one the
> fan switch is seeing -- it takes a while for the
> cooler water to make it
> back to the engine. But the fan is doing its job,
> keeping the water
> coming out of the radiator "cool enough" by
> assisting the airflow when
> necessary. This temperature is only *indirectly*
> related to the
> temperature of the water leaving the cylinder heads.
>
> Another thing to keep in mind is that the temp gauge
> on the dash is
> bimetallic and has quite a bit of lag itself. If I
> see a temperature rise
> on my aftermarket gauge it's generally 30 seconds to
> a minute before I see
> the dash gauge respond.
>
>
> David Brodbeck, N8SRE
> '82 Diesel Westfalia
> '94 Honda Civic Si
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