Might take some searching, but try to find a product like those pictured below, i think people have been able to find them on Ebay since the EPA shutdown deletes. Issue is there isn't enough positive pressure holding it together, so the O-ring will eventually fail again, you need to be able to apply positive pressure
www.cumminsforum.com
actually...just checked the links in that thread, still a live link with @Glacier Diesel Power so hopefully that fitting is still available, great fitting. Put one on my 12 to solve the issue as well
Leaking EGR delete coolant hose fix
So, first thing first, i have to give a shout out to Rich over @Glacier Diesel Power for helping me out on this one. 2 days ago, i found my coolant leak! it was the EGR delete coolant hose connection. what made this a real PITA to find, was that it was real intermittent to the leak was either...
actually...just checked the links in that thread, still a live link with @Glacier Diesel Power so hopefully that fitting is still available, great fitting. Put one on my 12 to solve the issue as well

'09-'12 Billet Standpipe Heater Hose Adapter
'09-'12 Billet Standpipe Heater Hose Adapter
www.glacierdieselpower.com