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Amsoil API Licensing

Q. Why aren't all AMSOIL motor oils API licensed?

A. Good question. Let us address API licensing in depth, as well as the issue of warranties. Some AMSOIL motor oils are API licensed, some are not. If you're concerned about your warranty and feel pressures to use an API licensed oil, even after reading this answer, then the XL 5W-20 (XLM), 5W-30 (XLF), 10W-30 (XLT) and 10W-40 (XLO) or our 15W-40 (PCO) API licensed oils should be your choice. If you are looking for an alternative to frequent oil changes or just want the best performing oil for your car, then one of our top tier non-API licensed synthetic oils are for you. Read on, and decide for yourself.

API Licensing - Passenger Cars - What is it?

An API (American Petroleum Institute) license indicates that a specific motor oil formulation has passed the minimum performance standards as defined by a series of laboratory bench, physical, chemical and engine tests. These tests were selected and minimum performance standards were set by the API Lubricants Committee to address specific areas such as engine wear, deposits, fuel economy, emissions, etc. The committee is comprised of representatives from automobile, oil and additive companies. The current specification is SM/GF-4 for gasoline engines and CI-4 Plus for severe-duty diesel engine service and CF for indirect injected diesel engine service.


The cost for running a test program for a single fuel efficient passenger car motor oil formulation is from $230,000 to $350,000, depending on if the formula passes the tests the first time through or requires multiple test runs or formula modifications to achieve a passing average (testing costs for heavy-duty diesel are running from $750,000 to $1,000,000). Once that testing is complete and the formula has passed all of the minimum requirements, it can be licensed for $1050 per year for non-members and $850 per year for members. There is also a royalty fee per gallon sold for all gallons over one million. The length of time between new specifications is now approximately 2 to 3 years, which does not allow a great deal of time to recover testing costs.

Who Licenses What Formulas?

Additive companies, such as Lubrizol, Afton, Infineum and Oronite, develop licensed formulas that they offer to oil companies to re-license. It is inexpensive to re-license one of these formulas, and the majority of oil companies choose to do this to avoid the costs associated with testing. This lowers the value of engines oils as the same chemistry is being sold under many brand names. Some of the major oil companies do have their own proprietary formulas developed, tested and licensed. All lubricant formulas from AMSOIL INC. are unique and proprietary.

Flexibility In Manufacturing An API Licensed Formula

API licensing was originally developed for mineral based oils, and it affords these oils more flexibility than synthetic oils.

Mineral oils comprised of Group I and Group II petroleum basestocks may use a simple program called base stock interchange for added flexibility in manufacturing and purchasing. Interchange means that by completing the proper paperwork and running a few minor tests an oil company can choose to buy these petroleum basestocks from many different suppliers. This ensures adequate supply and competitive pricing. However, Group III and Group V base stocks are supplier specific and base stock interchange is not allowed. For example, if a formula was tested with an ester (Group V) base stock from a specific supplier, then only that supplier’s ester can be used. Complete engine testing would be required to use that exact same ester from another supplier and is not performed because of the associated costs. This inflexibility makes price negotiations with synthetic base stock suppliers very difficult and it increases business risk. Supply disruptions from only one source could shut down production. Click HERE for more information about Group I through Group V basestocks.

There is also something called viscosity grade read-across. Fortunately, this applies to both petroleum and synthetic basestocks although the better cold temperature performance of synthetics makes it more difficult to achieve in some situations. (That's another whole story). What this means is that if you properly formulate the lubricant for which you have run all of the API tests, there are guidelines that allow you to use that same basic formula to make 5W-20, 5W-30, 10W-30, etc. viscosity motor oil.

Finally, there is a rule for substitutions in the CMA (Chemical Manufacturers Association) code of practice that allows a small degree of flexibility for all formulas. It allows a company to make changes of certain components in the formula with limited testing and paperwork requirements, provided the additives are at the same or higher concentration.

Key Limitations For API Licensed Formulas

Phosphorous content - .06% minimum to .08% maximum (API SM; 0W-20, 5W-20, 0W-30, 5W-30, 10W-30 viscosity grades, only)

NOACK Volatility - 15% maximum

The prevalent sources of phosphorous in motor oils are additives called zinc dithiophosphates (ZDPs). These versatile additives contribute to reduced oxidation, corrosion and wear. The automobile manufacturers, however, have demanded that lubricants contain a maximum of only .08% phosphorous. Their reason is some manufacturers believe higher phosphorous content levels will poison the catalytic converters on their cars before they reach 120,000 miles, which is the number of miles that vehicles are required to pass EPA emission standards. There is not total agreement within the automotive and lubrication industry about whether phosphorous levels over .08% actually do harm catalytic converters in the long run. What they have failed to make allowances for is the NOACK volatility of an oil, the volatility of the phosphorus itself, or the oil drain intervals.

The maximum allowable NOACK volatility percentage for the SM/GF-4 passenger car motor oil specification is 15%. Most of AMSOIL motor oils are in the 5% to 8% NOACK volatility range. There is a correlation between NOACK volatility and oil consumption, which ends up in the exhaust gasses. Therefore, higher phosphorous, low volatility oils present no more risk to catalytic converters than low phosphorous oils with higher volatility. This has also been demonstrated for years in actual application through state mandated exhaust gas testing on our Dealers' and customers' high mileage vehicles using AMSOIL synthetic motor oils. State inspectors are continually amazed at the low emissions levels generated by vehicles using AMSOIL products. So much for poisoning catalytic converters.

Why Some AMSOIL Synthetic Motor Oils Are API Licensed And Some Are Not

1. Full API licensing puts AMSOIL INC. in an inflexible position. Not only would we find it necessary to buy formula components from specific vendors and be at the mercy of their pricing and availability, we would not be able to make any major improvements to the lubricant formulas for 2 to 3 years without new testing and the associated costs. To solve this problem, the API must establish base stock interchange guidelines for synthetic basestocks just as they have for other basestocks, as well as develop interchange guidelines for other components too.

2. Full API licensing would impose strict phosphorous limitations on our motor oils. AMSOIL INC. disagrees with this limitation and feels strongly that consumers benefit from long drain, low volatility oils that pose no threat to catalytic converters. To solve this issue, the API and vehicle manufacturers must develop tests and make exceptions for high phosphorus, long drain interval, low volatility oils.

Warranties And API Licensed Motor Oils

Fortunately, the law does not allow manufacturers to "void your warranty" simply because of the brand of oil you use, the specifications it meets or the miles you drive between oil changes. To be specific, they cannot deny fixing your broken radio, faulty valve or cracked piston because you used an AMSOIL non-API licensed motor oil, or because you've gone more than 3000 miles since your last oil change. Denial of warranty coverage must be specifically due to an oil related failure. Courts of law will find against any manufacturer or dealership that tries these warranty shenanigans. If any automobile dealership insinuates that your warranty will be void if you use AMSOIL products or utilize extended drain intervals, let AMSOIL INC. know the name of the Dealership, the address, the owner's name and the name of the employee that made this statement (Read the AMSOIL Limited Warranty).

How Does AMSOIL INC. Ensure Their Products Meet Or Exceed The Minimum Specifications Of The Tests Required For API Licensing?

First, AMSOIL INC. works closely with major additive companies to select the top performing, and usually most expensive, passenger car and heavy-duty diesel motor oil additives. These additives have already passed all of the API licensing requirements in a petroleum or synthetic based formulation. Then we work with the additive company to maximize the amount of additive used and to boost the additive package in selected performance areas to achieve an optimum performing additive package for reduced wear and extended drain intervals. This is unlike other oil companies who, because additives are expensive, use the minimum amount of the least expensive additives required to meet the minimum API requirements.

We then utilize a blend of synthetic basestocks with known performance characteristics as a replacement for the petroleum basestocks to optimize performance in areas of lubricity, volatility, viscosity index, oxidation and nitration resistance, pour points, flash points, deposit control, soot handling, emissions, etc. We also will utilize a high quality V.I. improver with better viscosity and cleanliness properties. This replaces the inexpensive, low quality V.I. improver used in the API licensed petroleum formula. We do laboratory bench tests before running field tests to verify the superiority of the synthetic formula in actual use. We also continue to monitor the performance of the oil through close scrutiny of tens of thousands of oil analysis tests per year across a wide variety of vehicles all around North America and the World. AMSOIL INC. has been collecting used synthetic oil samples from passenger cars since 1982. No other oil company has such a vast database of the performance of synthetic lubricants over extended drain intervals.

AMSOIL INC.'s products and formulations outperform API licensed oils. They're engineered that way. Period.


AMSOIL INC. takes pride in never having conformed to industry norms or standards when those standards are contrary to peak performance. We introduced synthetics to the automotive world in 1972 with the first synthetic motor oil to exceed API performance specifications. At that time other manufacturers refused to recognize the superior performance of synthetic motor oils. Now, however, most companies sell synthetic lubricants, vehicles are factory filled with synthetic motor oils and gear lubes, and some manufacturers even offer extended warranties if you use synthetics. AMSOIL has always offered extended drain intervals because the oil was capable of performing for extended drains, and it was the right thing to do for the consumer. Now the entire industry is moving in that direction. Ironically, GM is now extending drain intervals (as much as 12,000+ miles) through the use of their oil life monitoring system, and some foreign automakers recommend 10,000 mile and longer oil drain intervals. Additionally, competitive oil companies are now extending drain intervals and even Mobil is recommending 15,000-mile oil drains for oils that are not API SM licensed.

AMSOIL is a company of firsts. That doesn't happen by always conforming to industry norms and standards.

API licensing of lubricants is voluntary, and it ensures automobile manufacturers and consumers that the product meets a set of minimum standards. Should these standards, in the future, be raised to a level consistent with AMSOIL's standards for motor oil performance, AMSOIL will consider licensing all oils. For those that feel pressured to use an API licensed product, we have them and encourage you to use them (XLM, XLF, XLT, XLO and PCO). AMSOIL does offer better performing motor oils that are not API licensed for all of the reasons explained in this response. They provide our customers with alternatives to the commodity products typically available in the market today. If you want the convenience of extended drain intervals or the top performance from your vehicle, AMSOIL has taken time to engineer the very best money can buy.

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