results to share w/ folks....

Car: 1995 Saturn SL1 SOHC.

Symptom: Temperature gauge reads temperature but engine is running cool.
Temp Gauge below typical running temperature. About 2 minutes after car
starts running the radiator fan starts and runs until ignition is off.
Season is summer; environmental temp is about 27 deg Celsius. Typical
drive is 60 minutes duration. Engine is not overheating. No leaks in
coolant system/hoses, reservoir level is good. Coolant mix is
ethylene-glycol coolant with distilled water in a 70:30 ratio.

My thoughts: From reading my Haynes manual, it appears the thermostat is
stuck open. However it appeared to be also a sensor problem as the fan
is running on....

Troubleshooting:
1. Wiring harness ok
2. checked the PCM/CCC/computer trouble codes = code 14 only. Temp
sensor high temp.
3. I replaced the engine coolant temp sensor and viola the problem is
resolved. The new sensor (Niehoff) has a brass body at the sensor tip.
The original was a plastic body and it appeared to have a small crack in
the body. I hear there's alot of trouble with these. Anyway lookup a
great how-to-fix video on Youtube ... very well done by Richard
("richpin06a") http://www.youtube.com/watch?v=JC0U53w_Htk
4. I did not replace the thermostat.


Cheers, Roger