Are you confusing bypass with anti-drain back? I've only heard of oil pressure by-pass as being a function of the filter housing, if it exists at all.
-Ah, we posted one minute apart, never mind.
I had a friend at an independent BMW shop that was on an oil change interval and filter Jihad, around 2005 or so. BMW had some recent models out with extended oil filter changes, as in 2year oil changes. He had a filter on his website from a BMW certified pre-owned vehicle that was brought in for some engine issues, and he cut the filter in half to show how bad an idea it was to go that many miles/years with out changing the oil filter. It was black jelly inside the filter, which was clearly a BMW filter. It took a lot of time to clear that engine of sludge, IIRC.
86 spider Veloce
Last edited by John533i; 10-20-2017 at 11:44 PM.