I have a little over 10k on my 24 Tacoma. I am a few changes in, and just switched to HPL 5w30 PCMO. The motor now feels smooth as silk too. I'll probable switch to the HPL 0w30, but I have to work through a couple cases of the 5w30 first. I have similar concerns as you as far as OCI, I plan to keep this truck 10-15 years so I want to go a little overboard. Running a good off the shelf M1 ect, oil, 4-5k is pretty conservative but was my plan. Now running HPL, I will probably go 5-6k and not worry if I go a little over that, due to being busy. I know the oils are good for longer than that, I just do not want any sludge, varnish or piston deposits if I can help it and I think that keeping OCI's short, especially HPL should help with that.
Now my non turbo 4runner, whith a long proven and solid engine, gets HPL and will probably get changed around 10k+. Oh, BTW, If you put 5.9 Qts in, it will be a little over filled (with filter change) Add a little over 5 qts and check. I think my truck uses about 5.4.
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