Low Engine Coolant Temp?

[JimT]

Every since my Inframe last year the engine coolant temps have been consistently steady at 178 F. Climbs as expected under loads and on hot days, but always cools down or returns to 178 (both dash gauge and Insite report the same temp).

Otherwise the system seems to be operating normally. Fan kicks on or about at 210 (happens so infrequently that I haven't scrutinized it). Even when fan runs for AC the coolant temp might briefly dip below 178 but bounce right back up and hold steady.

Is that a problem? I know normal operating temp is supposed to be 185 on the low end. It got a new thermostat (from the rebuild kit) and oil cooler during the inframe. Don't remember if there was a new temp sensor in the kit. Prior to the inframe the running temp had been steady at 195 F. Only other difference is exhaust gas no longer reaches the EGR cooler since a plug was also installed during the inframe.

[Rawze]

sounds fine to me. It is not uncommon for there to be a bit of variance from one replacement thermostat to another. As long at is is well regulated and close to what the excepted temps should be, its doing its job.

[JimT]

Ok, cool. I know these engines are designed to perform optimally within a certain temp range. It's highly consistent / well regulated, just below the stated 185 F. Just wanted to make sure it wasn't a problem that needed addressing. Thanks.

[Nilao]

My Peterbilt sits at 179 on flat land. you have to remember that 185F temp is the temp its trying to maintain. where the coolant sensor is might be 178 the coolant at the t-stat could be 185.