Hello all,

Trying to diagnose a closed-loop erratic idle, I measured the coolant temp
in the expansion (not overflow) container, and found it to be on low side:
120 to 130 degrees F. at ordinary, around town, temperatures. At this temp
the gauge rests near the bottom, on the white mark. That's how it almost
always is when driving around town. Isn't that low?

I know that "real" coolant temps should be measured at the water pump. But
given a 20 degree difference between the container and the pump(I'm
guessing) isn't that still on the low side?

Driving home from T-Day dinner, about 50 miles on freeway, the temperature
never got up to the white mark on the gauge, and the engine stayed in open
loop all the way! I know that the Temp 2 sensor is good because I've
replaced it twice in the last six months and the two I took out test good as
well.

1984 1.9.

How hot should they run?
Would cool running affect idle?
Anybody run the thermostats that open at higher temperatures?
How much of a PITA to install?

Thanks!