So what temperature should the car be running at under normal conditions?
Well, if your running a stock thermostat, then once the engine's warmed up, the temp shouldn't run less than 190-195 degrees F. (rating of thermostat). The thermostat just controls the minimum operating temperature that the eng. can run. And as it heats up, most cars are set to kick the low speed mode of the cooling fans on at around 210-215 degrees F. So I would hope to see it somewhere in that range upon fan engagement. You should be able to check it while idling, and see it progressively rise up to the high end, and then watch the cooling fans kick on, and then progressively watch it go down to around 200 Deg. F. before you see the fans turn off. The temp may get as low as the thermostat rating on a cool day while there is windspeed air flowing through the radiator (car moving), but if the thermostat gets stuck OPEN, chances are that the engine wont even reach operating temp while cruising down the road (w/ radiator airflow). And on a really hot day, if low speed fan mode is not enough to keep engine cool while not moving (no radiator airflow), then you will hear the fans spool up to high speed operation. I think that happens around 220 deg. F on most cars. Also, if the A/C is turned on, fans run all the time, because the A/C condenser needs air flow to carry the heat out of the refrigerant that is passing through it
