Only time i ever replace a heated core is when it leaks.
Flushing 2 ways.
Ten minute rad flush and a pump to circulate it through just the core, i mix it with hot water.
Other is a funnel jammed into heater hose and a blow gun.
Drop in a cup of water and follow with compressed air.
Reverse hoses. Catch what blows out, otherwise you will never know if core is plugged or not.
Did mine yesterday and it was not.
Being a chrysler product, the pink coolant lasts 5 years. Then it starts leaving deposits in the cooling system. Wanna see?
View attachment 1715268574after much headscratching trying to figure out what caused a jeep to overheat, i replaced rad and cut old one apart.that stuff is like sand. Owner said he bought it with low mileage.guess coolant was never changed.