Finished engine oil is comprised of 70-90% of base oil and 10-30% of additives.
Base Motor Oil Functions:
Motor Oil Additive Functions:
Base Motor Oil Properties:
Grade |
20 | 30 | 40 (0, 6, 10w) | 40 (15,20,25w) | 49 |
mPa.S @ 150 Celsius | >2.6 | >2.9 | >2.9 | >3.7 | >3.7 |
American Petroleum Industry is the primary standards body for engine oil in North America.
ILSAC (International Lubricant Standardization and Approval Committee) represents the interest of American and Japanese manufacturers to the API.
Both API and ILSAC use an alpha numeric system to superseding approvals.
Year | API | ILSAC |
1994 -1996 | SH | GF-1 |
1997 - 2000 | SJ | GF-2 |
2001 - 2004 | SL | GF-3 |
2005 - Present | SM | GF-4 |
The API trademark "starburst" and "donut" communicate the performance level of the oil to the consumers.
The primary weakness if the API system is the inability to position one approved products as an upgrade to another. Car manufacturers produce cars with vastly different performance levels, but the oil standard is exactly the same. This has spawned the widespread use of the word "synthetic" to denote an upgrade product, rather than a quantifiable performance improvement.
The Association of Constructors of European Automobiles, is an auto manufacturers association, and geared to the requirements of the cars more so than the oil companies. This has allowed the manufacturers to, push a long drain regime that reduces oil usage but improves the overall quality of the oil.
BMW Approved TOTAL QUARTZ Lubricants
Criteria |
Gas |
Diesel |
Low SAPS |
Drain Interval |
Fuel Economy |
A1 |
B1 |
C1 |
<15,000 kms |
High Performance - Turbo + Extended Drain |
A3 |
B3/B4 |
C2 |
>15,000 kms |
High Performance + FE + Extended Drain |
A5 |
B5 |
C3 |
<30,000 kms |
Fuel Economy
Most new cars sold in Europe are diesel or turbocharged, these engines require thick film oils for maximum protection.
Most new cars sold in North America have large displacement, low revving, naturally aspirated engines which deliver significant fuel economy benefits from thin film oils.
The push for fuel economy from ILSAC and API, couples with the lack of HTHS viscosity limits, promotes low viscosity engine oils that compromise long-term durability.