Coolant loss

[Paulywantsacracker]

So i confirmed the missing coolant is ending up in the fuel tank , from what i gather it needs injector cups installed , is this correct? Or is there a different way it can get into the fuel ?
2012 pete , 2250 , demandated ,43000 miles on engine
In the future i want to get into doing this type of work but for now i am 3 years behind on other tractors, trailers and vehicles to service and i have zero tools for this , i have to get peterbilt to do it for me ,is there anything else they should be doing while they are at it ?