mr wilks wrote: ↑Mon Jan 02, 2023 10:03 am
@XMetal
have you a record of what oil brand + spec you were using on the individual tests from 28k to 54k ?
Yes - If you look at the original oil analysis that I've posted, look toward the bottom of the first section will show what oil and additives. I've mostly used the OE Castrol 10W60, but since I've started seeing the higher lead wear, I've decided to try different viscosity and various additives to test out everyone's theory that I've came across regarding this topic over the years (I'm an engineer, so I like concrete data vs just "theory"). Since seeing the high strings of lead, I knew that I had to do my bearings sooner or later, so not much harm in trying out various things. As you can see from the analysis that nothing really helped. This lead me to believe that the original bearings probably didn't get installed (torqued) down properly from the factory - probably BMW didn't put their top techs building the later engines or they just let their torquing equipment go out of specs? Since the rod bearing change, I've only use LiquiMoly 10w60 and Castrol 10w60 - no difference in wear.
I have no track time on the car. Car doesn't get past 3.5k until oil is fully warmed up (I live in Southern California, so weathers are mostly in the 70s F to 90s F year round) - can't blame the 10W60 getting properly up to temp. My oil change interval is annual since I don't drive that much, but the last change was 1.5 years since I've only driven it around 3k miles - can't blame the lack of service. The car doesn't consume a drop of oil up to this date. My driving habit hasn't changed over the years, so...can't say that I've treated the car any differently pre/post bearing change.