David Allen Johnston
I can’t say specific information on this car, but check your fan relays, and ensure climate control isn’t on. The heat exchange for it is normally directly in front of the radiator and causes the fans to run when not moving. Also check the temp of coolant and trans oil with a 2nd method like scan tool and thermometer, trans oil cooler is built into the radiator and if the temp sensors for it or the block jacket, or gage read wrong you will chase your tail forever. the nipples being broken off, I suggest a radiator shop. If not an option find out if screwed in or sweated in. screwed you need a nipple wrench any hardware store should have. If sweated in, time for specialized skills and fire control, because it takes a torch and solder & flux to do right. Otherwise, buy a tap and threaded nipples in same pitch size that’s slightly over what broke off, and go slow with lots of lube, backing out the tap every 1/4ish inch. Sorry I can’t be more specific, but I like my Dodges slightly more experienced. Good Luck.