2000 Silverado heater core busted the first inch or so off the white plastic nipple I guess you would call it the shank does it twist off? Any suggestions welcome

 

For as cheap as a heater core is just replace it

 

For anyone else that is looking at this job. Two quick connect nipples at the firewall one black one White. White one is ten bucks more then the Black guess which one is broken? So says special tool required for removal. Anyways the quick way seems to be cutting it off combination dremel and hacksaw blade real tight quarters care should be taken not to cut the core inlet tube. A O-Ring is also required. Replacing the core by the book requires discharging and removing A/C box and dash removal and looks like cutting these connects for removal. If the core craps out it I think it will be someone elses problem