Originally Posted by
az3579
See below.
Dario's is a perfect example of the oil not being the culprit. There is an approved oil being used, yet still has sludge buildup. That sludge buildup may or may not be the cause of mileage driven on the oil, or other maintenance habits that attributed to this. Who knows what the history of the car was before he got it.
So, sludge, lifter tick, and whatever engine problems could easily be attributed to a number of other factors other than the type of engine oil used. Granted, you definitely have to make sure it's synthetic oil as that's what our engines are designed for, but other than these very few reports of miscellaneous oddities there are countless of cases of folks who don't use LL-01 approved oils that are just fine. Just ask anyone who uses a non-approved oil and has an engine that is fine *raises hand*. The ratio of folks that are fine greatly outweighs those who have problems when we talk about using non-approved oils. If this was a concern then this would be as widely known as failing window regulators or burnt ZKW bowls.
In the case of something like lifter tick - well, you've got to think about how the car is used. Does it get autocrossed? BMWs are notorious for lifter tick after an autox event. Did that owner perhaps run the engine without oil for a little too long? That's been known to happen as well.
In the end, your engine isn't going to magically give you all sorts of problems by switching to a different weight oil. The weight should be matched to the environment it's running in so as to get optimal protection, regardless of what BMW recommends.
Just as a side example, Mobil1 0W-40 is a LL-01 oil. Mobil1 is a very reputable brand that's been proven to produce oils that protect engines. So going to a 10W-30 from the same brand isn't reliable anymore just because it's not approved? That doesn't make sense to me.
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