Hello all, I have recently been somewhat paranoid about the timing chains in my 5.0, they seem slightly loose but have a documented repair from a year ago. My question is not about that though.

In researching this issue I hear very little about what causes the failures at such different times. I understand the mechanics of the aluminum guides and metal pins, but I don’t understand the correlation with poor/15k mile oil changes. I’ve heard of some with poor oil changes lasting 32k miles and I know people on this forum are approaching 200k on their originals.

What about the oil causes the chains to fail so rapidly? Are there any other circumstances that cause failure or at least accelerate failure? Such as lower octane gas, lugging the engine, high rpm, cold temps etc?

I’m seeking an answer about what mechanically happens to cause the failures and how these problematic behaviors influence it. Not just cause I’m concerned about mine, but curios about the intricacies of this issue.

Thank you for your insights!

 

I believe the theory's dirty oil contributing to tensioners failing. I've seen videos of bad ones, and they're sticky. Oil changes should be at 5,000 mile intervals due to carbon contamination. JLR revised the chain and tensioner design in 2013.

 

By sticky you mean that they aren’t lubricated enough to fully extend and fully hold tension? Thank you for the input!

 

Resulting in chains that would stretch, sprockets would have premature wear.
What’s interesting is that following the redesign, the same outcome occurs should a suitable schedule of maintenance (oil changes) not be adhered to. Of course this would typically happen after many more miles.

 

I do find that even at 5000 mile oil change intervals with premium synthetic 5w20 oil, the oil that is extracted is very black/dirty on these engines. I expect it is a direct result of the direct injection and carbon buildup effects. these carbon particles suspended in the oil would act as abrasives especially apparently on the timing chain rollers, cam gears etc. that coupled with the early design timing shoe allows a lot of slop on the chains...

 

Yes, the idea manufacturer's recommend 15K miles intervals and some as much as 20K miles is absolutely wrong, even the main dealer advises against it (initially at the introduction of the 5.0 they boasted of the engineering marvel of the engine design and Castrol formulation but soon changed against JLR recommendation)). A long time ago I let the oil go as high as 10K miles as an experiment and it was jet black, confirmed for me 5K was best.

 

i guess the good news is that although the LR uses 8 litres of premium oil [$$$] and a $30 filter at least with the desisgn one could change the oil in a tuxedo and 15 minutes if one chooses. :-)