We've discussed tensioner-related issues a lot on this board over the years. I think it would be helpful to summarize what we know. I'll start with a poor attempt and hopefully we can get to a consensus. 1) We all agree with the fact that the oil change interval should be reduced from the factory recommendation of 15k miles to 1/2 or 1/3 (5-7.5k miles) using a good synthetic oil of the proper weight if not using the expensive recommended Castrol oil. 2) Theory is that not doing so will impact tensioner function causing the chain to slacken and leading to bigger problems such as possibly skipping a tooth if severe enough. 3) There known are issues with the the guides wearing on earlier (pre ~2013) models. Aside from the point 2) above, but likely in addition to it, a deep pocket eventually is created on the aluminum guides causing even more chain slack. I think that summarizes my understanding of the issue. Feel free to add links for images/videos or expand. What I want to discuss is the "2013 fix." I know there are reports of "failures" or at least tensioner jobs on 2013+ and SCV6 LR4's. But we know there was a fix to the guides with a steel insert to prevent wear on the aluminum guides. The question I have is, are the tensioner issues on >2013's related only to chain slack (point 2) above)? Has anyone who has followed a known shorter oil change interval had any issues on a 2013+ model? Any evidence that the 2013+ guides are wearing? Any catastrophic failures on >2013 LR4's? My point is, it's possible that >2013's see tensioner/chain issues if oil change intervals are long. But since (hopefully) the guide wear issue is resolved, the magnitude of the issue should be less and hopefully eliminated with more frequent oil changes. This would also apply to pre-2013 vehicles with the updated guides. Could people chime in with tensioner/chain anecdotes and mention: 1. Model year 2. Known oil change history 3. Type and extent of issue (engine failure, CEL, noise) Anecdotes from Jaguars using the same 5.0L V8 would be helpful as well.