Gasoline all comes out of the same pipe, too, but then gets additives added.

Call me crazy, but for all these years I've used Walmart "Tech" brand oil. About a year ago I had to take the oil pan off my '90 124 to replace the oil pump. Not because of the cheap oil, but because a professional mechanic, at some time in the past, dropped a little ball socket into the engine... it eventually got into the oil pump and Bam! locked it up instantly. I must have driven a mile or so with zero oil pressure until I heard all the racket and shut it down (we idiots need an idiot light and not just a gauge.)

Anyway, the engine amazingly survived with no damage and, in spite of my cheap oil of choice, the inside of the engine was as clean as could be, with no sludge or deposits of any kind. And when I pulled the connecting rod caps to check the bearings, there was still a lot of oil in the bearings.

So, I'll just keep using the Walmart store brand, thank you.

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2012 E350
2006 Callaway SC560