2015 Cascadia coolant filter change.

Around 2015 they said you no longer need that filter if you use an OAT type antifreeze.
Detroit PowerCool Plus.
It's probably original antifreeze and should be changed out by now.

 

You could also try cleaning your radiators exterior. They can get pretty dusty and dirty just from use OTR.

I find that coil cleaner really helps clean things up. Also, taking shop air and reverse flowing air through the radiator really helps. Be careful not to bend the fins!

 

Valves turned back on? Coolant topped good, no air pockets? May need to let it run a couple hours with cap off, or loose, to burp it.

 

Do a coolant flush, however I will say don’t be surprised if you end up doing a coolant pump soon. Sounds like cooling system was neglected. Newer DD series engines no longer have coolant filters.

 

Maybe when you drained it, the thermostat got some crud in it, now it’s sticking. Definitely need to clean the fins in the radiator, take the ata cooler and a/c condenser off and clean them all good. Check fan operation, flush fill, replace hosrs, thermostats. Other than a plugged radiator core, which can be flushed with rust remover, but only if you’re a cheapskate like Me. Buys time.

 

Sometimes, if you drained and refilled the system air gets trapped. It usually works out over time, and you need to top it off. Mine for instance recently took an extra 2 gallons, after an OH, it was totally dry, new radiator. Even though I ran it for an hour, after filling it, with cap off, vent open. Yours being a closed system, may need to run a while with cap off, I’m just guessing, it could be a little harder to get the air out than mine. Often there’s a petcock vent on the high point in the system. On the top radiator (steel part) of hose. If so open it also, while running engine. till coolant comes out of the vent,( high point), to get air out.Hope this helps.