I've been running my m117 and om617 on various 15/40 weight oils for a few years now, with no complaints from either of them.

Getting the oil for $20/case lately has me using Delo 400, but when that runs out, who knows.

That being said, I'm looking at running a lighter weight oil for the om617 this winter, as it was a pain to crank up in the cold last winter.

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...