Latest analysis report is attached below. I had intended to change sooner than 11kmi, but didn't have time over the winter. I also had planned to switch to a different (less expensive) oil, however I got a deal (translation: 2022 pricing) on the same Red Line 5W-20 that I had been using, so the switchover will be delayed.
Of interest this time is that the oil level shortly before the change showed "Add 1 Quart" in the display. However, a couple hundred miles later on the day of the oil change, the level was "Below Minimum". It's really annoying that the V8 engine does not have a low oil warning. According to the service manual, the diesel engines have a low oil warning, but the gas engine do not. I also found inconsistent oil level readings on different days. In the future I'll start watching the oil level more closely as it gets near / beyond 10kmi or so. The level seems to remain ok until closer to 10k or so.
As you can see in the analysis history, the last change in summer 2023 was the first time I had pushed to a fairly long interval with Red Line... previously 6k max, then 11k. The results were concerning, TBN was lower than I expected.
This time, I was expecting similar results - but nope! Results were better! Over the same 11kmi, TBN was good and wear metals were also good (proportional to mileage). The Red Line additive package seems to have changed over the years, the current formula has a bit more ZDDP, a bunch more calcium, and far less magnesium. It seems the previous interval from spring 2022 to summer 2023 was harder on the oil than usual, maybe? There was no unusual activity during that time (no towing, extended city idling, etc) so I'm a bit confused.
You may recall the oil filter had partly failed at the 142k change (details
here). This time at 153k there was no failure of the filter element... however one small section was bulging where it should not be. Very odd. I'll try to get photos, and I need to upload photos of the previous failure. These are Genuine JLR filters purchased at the dealership.
I plan to do another 11kmi interval to get to 164k, followed by another 11k to get to 175k, after which I'd like to stick to a nice round 10kmi (or, 5kmi if switching to cheaper oil). Fingers crossed the 164kmi analysis will be similar to the 153k (good) numbers, not the 142k (not-so-good) numbers.
I'm half tempted to add 1 quart of fresh oil when the level gets to "Add 1 Qt", as this will boost TBN, and push the drain interval to 12k-15k. That would be after the 175k interval a few years from now, so I've got time to noodle on that concept. For now, the numbers look good, no excessive wear, and TBN is ok for the 10-11k interval.
Side note: This was only the second time I have used a vacuum extractor, and I was able to pull the pan drain plug after vacuuming. Almost ZERO oil came out of the pan, a fraction of an ounce, more like a healthy drip. Definitely no reason to pull the drain plug if you vacuum. Sweet! I measured the amount vacuumed, it was ~6.4 quarts (previous fill was 8.0 quarts), so ~1.6 were consumed over 11kmi, with increasing consumption starting around 7-10k or so.
