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 (http://www.sae.org) - 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 (http://www.api.org/) - 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.
International Lubricant Standardization and Approval Committee (http://www.ilma.org/) - opens a new
European Automobile Manufacturers Association (http://www.acea.be/collection/about_us) - opens a new window
JASO - Japanese Automobile Standards Organization
(http://www.jsa.or.jp/default_english.asp) - opens a new window
ASTM - American
Society of Testing Materials (http://www.astm.org/) - 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
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
SURFACE PROTECTION ADDITIVES
Anti-wear agents reduce friction and wear, help prevent scoring or seizure and help prevent metal-to-metal
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
Seal swell agents help to swell elastomeric seals by causing a chemical reaction in the elastomer.
Viscosity modifiers help reduce the rate of viscosity change when temperatures rise or drop.
Antifoamants reduce surface tension and speed the collapse of foam.
Antioxidants slow the rate of oxidation by decomposing peroxides and terminating free-radical reactions.
Metal deactivators are used to reduce catalytic effect of metals on the oxidation rate.
The question of phosphorus.
Phosphorus is the key component for valve train protection in an engine, and 1600ppm (parts per million) used to be
the standard for phosphorus in engine oil. In 1996 that was dropped to 800ppm and then more recently to 400ppm - a
quarter of the original spec. Valvetrains and their components are not especially cheap to replace and this drop in
phosphorus content has been a problem for many engines. So why was the level dropped? Money. Next to lead, it's the
second most destructive substance to shove through a catalytic converter. The US government mandated a 150,000 mile
lifetime on catalytic converters and the quickest way to do that was to drop phosphorus levels and bugger the
valvetrain problem. Literally.
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 (http://www.carbibles.com/fuel_engine_bible.html#20060828) for more
info on this. This also means that they don't get the coveted ratings of other oils but they do protect your
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.
The API has been criticized for lagging behind on oil standards compared to the European ACEA. However, be aware
that in the United States market there were motor oils available to the public that were performing at or above the
ACEA standards. Most consumers chose price over oil quality and performance, at least in the past, as Mobil 1 and
AMSOIL sales numbers were never impressive until more recently. In Europe the oil quality standards were forced upon
the consumer by the manufacturers. With ILSAC you now see oil standards set by the manufacturers in the U.S. market. In
Europe motor oil has reached very high standards with some manufacturers forcing specialized motor oil ratings on car
owners for the warranty even in the U.S. market where these oils are hard to find and expensive.
After reading this information you can better understand the terminology used throughout this website. I hope this
For more information also see: