Given the branding of O’Reilly motor oil, it should go without saying that the auto store chain is the primary retailer of its motor oils. It would seem, however, that O’Reilly does not manufacture their in-house brand of motor oil themselves, and even after investigating, we couldn’t confirm who makes it these days.

That mystery is partially due to Ozark Automotive being listed as a distributor on bottles of O’Reilly Auto Parts motor oil. The problem is that a little sleuthing confirmed that, though Ozark was once a sub-organization of O’Reilly, both the company’s website and storefronts have apparently shuttered. Searching “Ozark Automotive” on Google Maps, however, turns up several O’Reilly stores, so it’s worth wondering if Ozark wasn’t merely folded into the greater O’Reilly empire. Whatever the case, a little more digging also turned up a 12-year-old YouTube video from Omni Industrial, Inc., which makes clear that, at least at one point, they were, in fact, the company tasked with manufacturing and packaging motor oils for O’Reilly Auto Parts.

It’s uncertain whether Omni still makes or packages O’Reilly oil, with several posters in the comments section of that video claiming that Mobil 1 makes O’Reilly oil these days. However, we couldn’t find any concrete evidence supporting the claims. Ultimately, it’s still unclear who makes O’Reilly branded motor oil. But if you don’t mind using a motor oil with unknown origins, you can clearly do a lot worse than the O’Reilly brand. Given its price point, you can save a few bucks using it, too.