The Original Synthetic Motor Oil

How to Read an Oil Bottle - What do those letters and numbers mean ...really?

Before you can read an oil bottle it helps to understand what all of the abbreviations stand for that you may see posted on a bottle of motor oil. This information will deal specifically with the typical bottle of motor oil you will find at your local auto parts store in the U.S.

SAE - Society of Automotive Engineers ( - opens a new window
These guys set standards beyond those used in lubricants, but since this is the system most see on oil bottles dealing with viscosity, we'll list them first.

API - American Petroleum Institute ( - opens a new window
Created around 1930 they have set the standards for oil quality and performance in the U.S. market. The API is comprised of the major oil companies. In other words, for the most part oil standards in the U.S. have been set by the oil companies until recently when the JASO and ILSAC came into the scene. ILSAC, JASO and the ACEA represent auto/truck manufacturers that set oil quality standards.

ILSAC - International Lubricant Standardization and Approval Committee ( - opens a new window

ACEA - European Automobile Manufacturers Association ( - opens a new window

JASO - Japanese Automobile Standards Organization ( - opens a new window

ASTM - American Society of Testing Materials ( - opens a new window
You may not see these guys on a bottle of motor oil, but they set standards worldwide for everything from bolts to electrical wiring. Their testing methods show up on all things including lubricants and filters.

The information here is organized by sections on viscosity, API service ratings, JASO and ILSAC oil service standards. First I will give you a history of how these systems have evolved into being:
At one time motor oil was not additized and with poor filtration motor oil life was limited to around 500 miles oil life. As you can imagine, without friction modifiers engines didn't last very long and the absence of detergent (TBN) additives made oil degradation a serious problem. Combine that with the choice of poor quality base stocks made from Group I base oils, the first motor oils kept engines running, but not for a great length of time. Around 1930 the API was formed and oil standards were implemented. At this time the first API oil standard, API SA, was implemented. SA oils were not additized and therefore obsolete even before anyone could know how to label them. API SB oils employed a friction modifier to prevent excess wear on flat tappet camshafts. As more technology was introduced the marvel of oil chemistry saw oils developed that could fend off the effects of acidity and reduce the size of harmful particulate.

The European counterpart to the API was called the CCMC later the ACEA. The ACEA is comprised of auto and truck manufacturers who set oil quality standards. In Europe oil standards are designed by the engine manufacturers who consult with the oil companies to determine what is feasible and the cost to manufacture. The European ACEA oil standards are set up on a multi-tier system where a consumer can choose a higher oil standard or a lower price. Also this system allows some manufacturers to choose higher standards for warranty purposes. Recently some European auto manufacturers have gone so far as to set their own oil quality standards and require oils be certified for warranty purposes. This doesn't concern U.S. oils, but if you own one of these European autos you are probably already aware of the need to seek out the correct motor oil. If not, all you need to know is in the owner's manual. You won't see U.S. oils with the ACEA ratings except for possibly some high performance synthetic motor oils. ACEA oil quality standards are higher than API oil standards which is why you won't be seeing these ratings on most motor oil bottles. API standards are minimum and uniform which is why bargain brands sold at the discount store will carry the same API ratings as the major brands.

In 1992 the AAMA (American Automobile Manufacturers Association) and the JASO met and determined that the current system involving the SAE, ASTM and the API, called the tripartite system meaning three governing bodies, were much too slow in responding to the rapidly expanding and changing needs of modern day automobiles and light trucks only. The AAMA and JASO was concerned that this lack of timely response left them vulnerable to excessive warranty claims that could otherwise be reduced and/or avoided.

Therefore, they formed the International Lubricant Standardization and Approval Committee (ILSAC). The ILSAC was empowered to set minimum performance standards for gasoline powered passenger car and non-commercial light truck oils. The ILSAC and the tripartite system (SAE, ASTM & API) then joined together and formed the Engine Oil Licensing and Certification System (EOLCS). The EOLCS licenses oils approved through the ILSAC. The API provides the overall administration of the EOLCS system.

Now to compound things, a new specification called ILSAC GF was developed in order to meet the newest set of government regulations regarding fuel economy and long-term emission system performance and durability. The initial ILSAC GF-1 and API SH specification first appeared in 1996. In 1997 ILSAC GF-2 and API SJ specification was released which put increased demands on 0W-30, 0W-40, 5W-20, 5W-30, 5W-40, 5W-50, 10W-30, 10W-40 and 10W-50 motor oils in order to meet requirements for phosphorus content, low temperature operation, high temperature deposits and foam control.

ILSAC GF-3 and API-SL replaced ILSAC GF-2 and API-SJ in July 2001 with even more stringent parameters regarding long-term emission system durability and improved fuel economy as well as improved performance in the areas of volatility and deposit control, viscosity retention, additive depletion over the oils service life and reduced oil consumption rates.

As the JASO and ILSAC were formed and created their own improved standards, the API moved quickly to introduced their own upgrades which, for the most part, paralleled the JASO and ILSAC standards.

What's in This Stuff Anyway?

It has been a long time since motor oil was just oil. In the 1930s a wax modifier was added to oil to address the problem of wax residue after the refining process. Thus began the use of additives in the formulation of motor oil. Today, motor oils contain a variety of ingredients designed to improve their performance capabilities.



Corrosion and rust inhibitors are used to prevent corrosion and rust on the internal metal parts of the engine.

Detergents keep surfaces free of deposits. Dispersants keep insoluble contam


Pour point depressants enable lubricants to flow at lower temperatures by modifying wax crystal formation, thereby reducing interlocking.




Antifoamants reduce surface tension and speed the collapse of foam.

Antioxidants slow the rate of oxidation by decomposing peroxides and terminating free-radical reactions.


The question of phosphorus.


In the US, Mobil 1 originally came out with the 0W40 as a 'European Formula' as it was always above 1000 ppm. This initially got them out of the 1996 800ppm jam and knowledgeable consumers sought it out for obvious reasons. Their 15W50 has also maintained a very high level of phosphorus and all of the extended life Mobil synthetics now have at least 1000ppm. How do they get away with this? They're not classified as energy/fuel conserving oils and thus do not interfere with the precious government CAFE (corporate average fuel economy) ratings. See the section on the EPA and fuel economy in the Fuel and Engine Bible ( for more info on this. This also means that they don't get the coveted ratings of other oils but they do protect your valvetrain.

Other manufacturers of performance synthetic motor oils, such as AMSOIL, do not even bother to have API or ILSAC certification on their top end high performance synthetic motor oils. Why? First off notice which oils AMSOIL actually does have API and ILSAC certification on. It is the less expensive, short oil drain motor oils. This is so their Dealers can sell bulk quantities of these motor oils to fleets and municipalities that may strongly require API and/or ILSAC certification. AMSOIL believes the 300,000 to 500,000 dollars required to certify these motor oils excessive and they are unwilling to comply with the reduced phosphorus (zincdithiophosphate also spelled zinc dithiophosphate or zinc dialkyldithiophosphate - abbreviated ZDDT - a friction modifier) especially since their higher priced performance motor oils are designed for extreme performance. Also, if a company wants to make any changes in formulation, they must once again resubmit the oils for certification and spend another 300,000 to 500,000 dollars. They limit the certified motor oils to those most designed for bulk use and less likely to need immediate formulation changes as new technology emerges. I use AMSOIL as an example because I am intimately associated with this company and know how they develop their market. But other companies that manufacture synthetic motor oils other than Mobil and AMSOIL are also dodging the API and ILSAC certification in favor of better performance and wear numbers. More detailed information on this follows about the API read across approval and how this doesn't fairly measure phosphorus levels reaching the catalytic converter. Basically, API standards are not worth dropping your standards for if you target a higher level of performance and have extremely low volatility.


After reading this information you can better understand the terminology used throughout this website. I hope this helps.

For more information also see:

Valid XHTML 1.0 Transitional