DD15 low coolant temperature

Mine hangs at 100 +/- always.
Same truck, same engine.

 

My bad....200

 

Maybe I’m missing something here…….How do you know the thermostats are working properly?

It sounds like they are opening too early to me. Shoot the rad pipes with a temp gun. Upper hose should be cool until they open. Engine fan is off?

 

Was going to say, but I was so far off the first time, I was reluctant.
That said, the gauges in my Cascadia are so completely unreliable I wouldn't sweat it unless something else tells you that something is wrong.

 

Have you tried bumping idle up while idling to 900 what they call for. I would say thermostats May be faulty or bad gauge reading. Only way to know for sure is pull t stat and test them.

 

Need to boil stats, check water temp with a thermometer when they open, and close. Sounds like one is sticking open. Might even have 160’s or 170’s. Sometimes once they get too hot, they will work erratically. So I’ve heard. Get some 180s or 190s if so. Whatever it calls for. If they check out. Should be good. Maybe gauge or sensor? Sometimes an early sign of head gasket trouble, especially if you’re losing heat to the cab. Should still get warm/hot at 150. Can’t trust the gauges.