what grade oil do you use?

[m3f_DLite]

10w-40 Castrol semi-syn

[m3f_Adam E36]

Amsoil 15W-40.



I've been using Shell Rotella T6 5W-40 in my 328is (M52 engine) and that works well.

[m3f_Rogacki89]

I use either Castrol or Total 15w-40, whichever I have put in at the time of change. I heard the S52 should use normal oil and not synthetic. Any real difference besides how long the oil change frequency is?

[m3f_Sharocks]

Liqui Moly 5W40.

[m3f_RickO1]

I heard the S52 should use normal oil and not synthetic. Any real difference besides how long the oil change frequency is?

Not sure where you heard this, but I don't think there is any merit to this. The biggest difference between "normal" oil and synthetic, is the basestock oil used. A normal or mineral oil is refined from crude oil, where the best oil molecules are extracted using several refining processes. The synthetic base oil is actually built up, essentially a custom molecule, that far exceeds the mineral base oil in its viscosity characteristics and high temperature stability. The mineral oil requires far more viscosity improvers and modifiers to get it to flow at low temps and not thin out too much at high temps. The synthetic molecules have much better viscosity characteristics at low temps and high temps, just by themselves. The synthetics are much more stable at higher temps, which is why they are used almost exclusively in racing engines. They don't breakdown nearly as easily as the mineral oils.



In my book, true synthetics are far superior to mineral based oils and I would never put a mineral oil in my M3, much less anything else I drive. The primary reason you can run them longer than the mineral oils is the stability of the base oil molecule.

[m3f_Bimmerman325i]

My car's been happy with Rotella T6 5w40.


I'm honestly amazed how many times this topic appears when there's a handy search function at the top of the page. It's not like searching for "oil" won't bring up 300 of these threads or anything....

[m3f_cky751]

10w 40