Castrol GTX doesn't have boron or moly, does it? Both show up in this report. My guess is that if the OCI really was 25K miles, it had several quarts of make-up oil added, possibly w/o the owners knowledge/memory.
The oil sheared long ago, and then began the process of thickening. The TBN is due to the additional oil added, which may have been 10w30, 5w30, SAE30, 15w40, who knows.
That's my guess.
The oil sheared long ago, and then began the process of thickening. The TBN is due to the additional oil added, which may have been 10w30, 5w30, SAE30, 15w40, who knows.
That's my guess.