Good Day Fellow Listers,

Colorado has had a cold November; my 1987 Syncro is protesting by
insisting on idling at 2000 rpm when warm.  The Syncro starts and
idles perfectly when cold.

I suspect that either the temperature sensor or the idle air
control valve no longer understands "warm".   As a quick test I
pulled the connector off of the idle air control valve, and the
engine immediately dies.  I pulled the connector off of the
temperature sensor (on the thermostat housing) and there was no
effect on the idle.  Looking at the Bentley manual, temperature
vs. resistance chart, I determined that resistance at the
temperature sensor decreases as temperature increases.  I jumped
the connector (simulating 0 resistance) and the idle decreased to
around 1000;  still a bit too high but much better.  Prime
suspect has become the temperature sensor.

Questions:
Do some / most of the technical experts on the list agree that
the temperature sensor is the most probable culprit?  Do these
sensors have any history of failure?

When replacing the sensor, will huge amounts of coolant attempt
to escape from the system when the sensor is removed?

Please respond directly to me as well as to the list;  I travel
on business a lot, and don't always have time to review all of
the lists when I get home!!

Regards to all,
Jon B Kanas

Longmont, Colorado
Cultural Center of the Universe
303-678-0658
kanas@qadas.com