Originally Posted by Cartronics
...What...really bothers me is that when i went to purchase my oil filter from the BMW parts center, i had asked what oil they use and they said 5W-30 part synthetic. Now when i open my hood it clearly says to only use full synthetic oil only...
Greetings from a former Miami-dweller who can now afford a recent model BMW (I had to move out of Miami to make that happen).
story on this one. A full explanation will be too lengthy. Search for threads on this. But in brief: As a result of a lawsuit (Castrol vs. Mobil)/trade dispute/arbitration, etc., type III motor oils that meet certain performance requirements can be labeled as "synthetic", except in Germany
. Type III are very highly refined natural (dino) base stocks. Type IV are the true synthetics because the molecules are synthesized.
I think when these motor oils are labeled "full synthetic" it really means "type III base stocks or better".
The OEM BMW 5W-30 and all the Castrol Edge SPT are type III except for the "European Formula" 0W-30 "German Castrol".
I've been doing a lot of research on this lately. It seems that high quality type III motor oils are OK and it's more important to look at the performance stats for the oil (viscosity, flashpoint, HTHS, etc.)
Does anyone know and specific advantages of type IV base stocks over type III?