What BMW Longlife approvals are
BMW Longlife is BMW’s system of oil approvals, identifying oils the manufacturer has validated for use in its engines. The approvals are often associated with extended service intervals, which is reflected in the “Longlife” name. Rather than a single specification, Longlife is a family of approvals that carry codes such as LL-01 and LL-04.
These codes correspond to different engine and emissions requirements. LL-04, for instance, is a low-SAPS approval — using reduced sulphated ash, phosphorus, and sulphur — which makes it suited to vehicles fitted with particulate filters and other sensitive emissions hardware. Other Longlife approvals address different combinations of engine type and regional requirements.
How they relate to viscosity
A Longlife approval describes the performance and chemistry level an oil has been validated to meet, but it is not the same as the viscosity grade. The grade — for example 5W-30 — describes how the oil flows, and it is a separate requirement.
For your engine, the oil should meet the Longlife approval your manual calls for AND the correct viscosity grade. Both pieces of information matter, and a product meeting only one of them is not a full match.
What to follow
Because Longlife approvals target specific engine and aftertreatment setups, they are not all interchangeable. Using an approval that does not match your vehicle can be unsuitable, particularly where particulate filters are involved.
The owner’s manual is the authority on which Longlife approval and which grade your specific BMW needs. When details are unclear, defer to the manual rather than assuming one Longlife approval can stand in for another.