Subject: [TR] TR4A Overheating problem conclusion

From: "Dave Connitt" <[email-masked]>
Date: Sat, 9 Nov 2013 16:39:00 -0500

I FOUND THE PROBLEM!!!
Last night I had removed the temperature sensor and basically profiled the
thing using my digital thermometer, my ohm meter, my wife's microwave (thanks
honey) and a plastic cup of water. I started at just under boiling out of the
microwave which was 205 F, then recording the resistance at 200, 190, 180...
down to 120 degrees.
This morning I replaced the sensor, started the engine and with my trusty
spreadsheet handy, I just connected my ohm meter to the sensor and watched.
As the engine warmed up, the resistance decreased. I have a 180 degree
thermostat and that was my first trip point. Sure enough, at about 190 the top
of the radiator was getting hot so I knew that at least the thermostat was
working. The resistance started to stabilize and still reduced but much slower
as now water was circulating. Then as if my magic, the thermostatic switch in
the down tube cycled on! I could watch the resistance go back up as the fan
cooled the water and the fan turned off. I waited a bit longer just to make
sure the fan was cycling on and off and it works prefect.
So, now I have to recalibrate my temperature gauge to my temperature sensor
and I should be OK.
The radiator I have installed has an additional row of tubes which helps too.
Thanks to all for your suggestions.
Regards,
Dave Connitt

** [email-masked] **

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