Mike Miller - such a great BMW enthusiast and member of the communityOriginally Posted by das boots
My S14 is presently being overhauled due to rod bearings knock....and then some more when we opened it up...Pandora came out.
But anyway, 3 local M3 S14 techs (all well known) plus Mike Miller highly recommend 20w50 conventional/mineral oil. Using synthetic was the cause of all the engine wear. 20w50 especially for SoCal weather. Synthetics for newer BMW engines.
"Initially, I agree that 5W-30 oil is too light for an S14 (and many other engines) unless you’re driving in Arctic temperatures.
As for synthetic vs. mineral oil, I don’t really care but it should be 20W-50 year-round in the San Diego climate. I use Kendall GT-1 20W-50 in engines built during the S14 era. Synthetic theoretically lasts longer but the S14 runs so rich I wouldn’t leave any oil in the engine past 5,000 miles.
Now, as for the engine wear, it could be the result of normal driving without enough oil viscosity, but it impresses me more as the result of racetrack driving and lots of it, probably with software that increases the redline, and possibly with detonation resulting from 11:1 compression pistons – they require racing fuel. Pump gas doesn’t have enough octane.
As for the Internet folks, you will get a different answer from everyone you ask about engine oil." - Mike Miller
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