The Topsider method works just fine. I'm using Amsoil full synthetic heavy duty marine and diesel oil in 15W40. I change it when the FSS reads 5000 and 0, which turns out to be about 6000 actual miles each time.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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