Another one to try might be Rural King's providence brand if there's a Rural King anywhere near, 8/gal in pails ain't a bad price, even 10/gal for individuals ain't something to complain about.
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It says it's syn-blend, although really the "conventional" offerings from most manufacturers are probably practically syn blend anyways since they're using high VI group II base oils like Exxon's EHC. They claim all the following specs, I don't see the providence name on the MB 228.31 list, but I do see Lubrigold, which this very well may be the same oil as the Lubrigold since it's made by Warren Oil and some of these tests like the Volvo T13 oxidation test required for VDS-4.5 are super expensive to run because they run for 360 hours straight, so I would think Warren probably reuses the same formulations for the several private labels they supply.
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