If cracked already, I'd just replace the entire UIM and plug the ports while you're in there. And pull all the spark plugs out and disable the fuel (pull the pump fuse or something) and spin the motor over a few times to clear out the cylinders. Then clean the plugs off, reinstall, and fire her up. Would recommend changing your oil and filter as well to be sure any coolant that has crept into the motor where it doesn't belong get out before you spin a bearing.