TS , A bit of an after thought , but it might not hurt to check out an RV forum for comments on the Motor Home . They may come off on the negative side re motor as they are not 6.5ers by & large I would think . So best to temper their comments with those on this site .
No experience with them but as write up indicates the nut provides more thread for plug to turn on & thus out ,rather than just spinning in place.
Seem to recall a fix described on the old site using tin or aluminum rolled tightly around the plug & threads cut in while turning the plug to...
Fwiw after my IP was changed engine would blow white at rpm,s over 2800 .Some black as well . It did clear up after some hours of driving & some wot s.
Remember those discussions ,More boost (more cooling air )produced lower inlet air temps up to certain pressures ,but going higher wjith boost produces opposite effect (higher iatemps) .Now starting to understand why (characteristics of stock turbo}.
I tended to ignore the the obvious rudeness as I felt Jif could /would handily take care of that aspect.but am happy that mitchedo addressed it to show support for Jiff .
I,m afraid I,ve grown too old to become involved in those kinds of discussions , but am still interested in the technical...