[s-cars] running cold after t-stat change

[Varon H. Fugman]

Patient: 1995 urS6, new 87C thermostat, new thermostat housing, new MFTS,
new blue coolant.  Car now does not warm up driving on highway.  Temp gauge
and climate control agree.  Today (with an chilly ambient temp of 56F) it
only warmed up to 59C (according to Area 51) after 10 miles of 65mph highway
driving.

 

1. New 87C thermostat was installed to replace the 80C thermostat that had
been installed at my last timing belt change.  I did test the new one in a
pan of water on the stove and it did open & close, although I did not check
the temperature at which it opened/closed.

 

2. MFTS replaced because I had never replaced it, so it seemed like a good
time while coolant was drained.

 

3. Thermostat housing was because of a leak. it appears to be made of the
same plastic as the heater-hose T fitting and after-run pump housing.  The
lip that seals against the t-stat o-ring was disintegrating and allowing
seepage.  The new housing has a difference from the original. it has a pair
of "fingers" inside which grab the thermostat.  They allow the housing to
hold the thermostat so both pieces can be installed on the engine together,
and they insure the thermostat is installed with the correct orientation.

 

I'm thinking either (a.) the new t-stat is defective and has stuck open or
(b.) the fingers on the new housing are somehow preventing the t-stat from
closing.

 

Any other theories?  Anyone else installed a new thermostat housing with
"fingers"?

 

Varon

'95 urS6 on the road again :-)