Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
That’s what I was thinking too, it’s time for the big tune up. If I knew that the swing in temp that I have been seeing is relatively normal then I’d leave the Tstat alone and just flush the system. But for a $10 part that relatively easy to get to I think it would be a mistake not to change it since the system needs to be emptied anyway.In my humble opinion, you've owned the truck for a year. You're approaching 100k.
Change the T stat, flush and fill the cooling system and then you will know.
Otherwise you are guessing.
If it continues to exhibit the behavior, then it's something else.
A flush and fill with a new t Stat is reasonable at 100k on the clock. Especially if it gives you peace of mind.
PS, the stock tstat is 203 degrees.
You already spelled out the problem, when your getting a CEL because the ECM is saying the temperature is too low then it's either the thermostat isn't working correctly or the coolant sensor is bad. Since you'll need to drain the coolant down to change either one might as well do both, use Mopar parts.I’ve noticed in cooler weather my highway driving temp can be as low as 175 degrees and then when I sit long enough it can climb up to 203 (never seen it higher than that). I usually let my truck warm up for 5-10 min in cold weather but if I don’t and pretty much getting going shortly after starting the truck I’ll get a CEL after a few miles that says that my engine operating temp is to low.