Thermostat?

[onebadapple]

Hello! ‘15 CM 2350 101 450 hp. For the last couple weeks when I cold start it, it is not warming up like it was. Even the oil temp is warming faster than the coolant. Once off and running, everything seems fine. When stopped for a bit in the cold (single digit and -temps) it gets a little below the 180° where it didn’t before. I also use a winter front with adjustable blockage. Ok, my old school logic is saying I need to replace the thermostat. Well, being fairly new to an ISX, is there anything else I should be looking at while I’m replacing the thermostat?

Thanks!!!