Quote:
Originally Posted by andrewwynn
Perfect. But M54 calls for 5w30. I have to go check the project farm review he does very comprehensive testing .
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Choosing oil by the labeled viscosity is very inaccurate. One 5W-30 can be much more/less viscous than another. Going by the BMW owner's manual is worthless, as it is written with the assumption that you take your car to the dealer for anything other than filling with gas.
It is much more accurate to go by manufacturer specifications (see newtis for more details), and the M54 calls for LL-01 oils as the minimum specification. MANY 5W-30 oils are too light viscosity to meet LL-01 including Mobil1. M1's 5W-30 never met LL-01, though M1's 0W-40 did meet LL-01 until the formulation change a few years ago.
To my chagrin, BMW is succombing to the fuel economy gods and beginning to recommend light viscosity oils. Their new spec is LL-01 FE. I suspect they will soon be recommending this new spec as backward compatible with our old M54's. Sad, as I bet the engineers who actually designed the engines would prefer a higher viscosity, but bureaucrats win in the end.
From a practical standpoint, and considering the way most of us drive these vehicles (relatively easy), you can probably get away with running almost any reasonable oil. I choose to stick with the oil that meets the LL-01 spec because it's what the engineer's specified and it's still readily availble at a reasonable cost.
AM.