KW T680 - coolant in diesel Cummins ISX15- cm2350

[Sreten94]

Fuel pump recently has changed tappets and was checked not even 10k miles ago. So far i serviced emission system was cleaned and new every sensor, doser and injector and new DOC catalyst. I will try to get inframe with it, but where I can get water pump and should I do the dumpener too?
Not really truck has been maintenened by KW by they didn't do really good job. Transmission is ultrashift auto 10 and i drive dry van between 20-45k ibs.