Let say I dont have the choice. All I can get is a complete UOA without TBN. Am I going to get enough information to tell when my oil is shot ? Let say, if a report give me contamination ok, wear ok, and oil ok (without TBN reading )should I conclude that my oil is doing ok ? Can I based my OCI or can I rely on this analysis without knowing if the TBN is ok or too low ? What are the other sign of an oil due for a change . Thanks for helping your favorite Frenchie !!!