I thought since it's letting more water in at 180, compared to 195, it's cooling it more efficiently? Maybe it was just a dying thermostat. Since after replacing it the temps dropped quite a bit. Definitely a noticeable change.

 

Something I learned today.

If you put in a 180° thermostat the engine doesn't reach operating temperature properly. The computer with react by adding more fuel....

 

Coolant temp will rise at the same rate whether using a 180 or 195 stat. A properly functioning stat ONLY controls minimum coolant temp.....other factors such as ambient temp, driving conditions and cooling system component condition determine max coolant temp.

Negative, a warm-up cycle is completed and counted by the ECU when coolant temp reaches 160. The O2 sensor(s) determine air/fuel mixture way before coolant temp is even close to 160. Since a heat cycle is counted at 160 and the ECU turns the efan on (if equipped) at 218 coolant temp (presuming no a/c clutch engagement), normal operating temp is anywhere between 160 and 218. Nowhere in the FSM is any specific coolant temp referred to as "normal"......not 180, 195 or 210.

 

Must have been a generic but of info possibly pertaining to newer cars :/

 

As soon as the O2(s) reach operating temp, the system will enter closed loop. Some heated O2s can reach operating temp in less than 10 seconds. Even in freezing cold weather, the ScanGauge shows our XJ entering "closed loop" 30-45 seconds after cold start-up and coolant is still cold.