The label found on lubricant packaging always brings the product specification.

The fact that an oil meets API classification CI-4 or CH-4 does not indicate that it may have a longer or shorter change period. As an example, in the case of the Lotus, the change interval is the same for both an API CH-4 and an API CI-4, but the vehicle's engine will have superior lubrication and protection, which may increase its useful life and its performance if the API CI-4 classification is used.

These are acronyms of international entities that are responsible for the elaboration of a series of norms (based on specific tests) for the classification of lubricants, according to their use. In this way, the consumer can identify whether the lubricant meets the requirements of his equipment, always consulting its manual.

SAE - Society of Automotive Engineers

It is the oldest classification for automotive lubricants, defining viscosity ranges and not taking into account performance requirements. It presents a classification for engine oils and another specific one for transmission oils. More information in "What do the numbers (20W-40, 50, etc.) that appear on oil packaging mean?".

API – American Petroleum Institute

Group that created, together with the ASTM (American Society for Testing and Materials), specifications that define performance levels that lubricating oils must meet. These specifications act as a guide for the consumer to choose. For passenger cars, for example, we have the API levels SL, SJ, SH, SG, SL, SM, SN, etc. Today we are already in an SN Plus or SN/RC. The “S” in this acronym stands for Service Station, or even SPARK (Spark) due to the use of Spark Plugs, explosion engines, and the other letter defines the level of performance. The first level was API AS, long obsolete, consisting of a pure mineral oil without any additives. With the evolution of engines, oils have undergone modifications, through the addition of additives, to meet the requirements of engine manufacturers with regard to protection against wear and corrosion, reduction of emissions and deposit formation, etc. Currently, the SN/RC level is the most advanced where the RC means “Resource Conserving” – Conservation of Energy Resources, such as emissions, Preservation of Turbo Systems and even specific for engines powered by Ethanol with up to E-85. In the case of diesel engines, the classification is API CI-4, CH-4, CG-4, CF, etc. The "C" stands for Commercial (Commercial Vehicles used to offer Services - always diesel engines) or "Compression", a specific operating process for diesel engines where there are no spark plugs and the explosion occurs by compression. The API also classifies oils for two-stroke engines and oils for transmission and gears.

ACEA - Association des Constructeurs Européens de l'Automobile (formerly CCMC)

European classification combines some API classification tests, European engine tests (Volkswagen, Peugeot, Mercedes Benz, etc.) and laboratory tests.

JASO – Japanese Automobile Standards Organization

Defines specification for the classification of lubricants for two-stroke engines (FA, FB and FC, in ascending order of performance).

NMMA- National Marine Manufacturers Association

Replaces the former BIA (Boating Industry Association), classifying lubricating oils that meet its requirements with the acronym TC-W (Two Cycle Water), applicable only to two-stroke outboard motors. Currently we find TC-W3 level oils, as the previous levels are in disuse.

The API GL-4 specification designates a service for passenger vehicle hypoid gears and other automotive equipment, operating under conditions of high speed and low torque or vice versa.

The API GL-5 specification is also designated for hypoid gears, operating under conditions of high speed and instantaneous loads (shock), a situation found in truck gearboxes and rear axles (differentials).

The use of an API GL-5 oil in the transmission instead of GL-4 will generate engagement problems, commonly called "scratching the gear" during gear changes, compromising the useful life of the gearbox. This problem is due to the higher content of additives in API GL-5 oils compared to API GL-4 and the use of specific components in the case of GL-5 Lubricants, which end up negatively interfering with the operation of the gear synchronization mechanism.

These numbers that appear on the packaging of automotive lubricants (30, 40, 20W-40, 5W30, etc.) correspond to the SAE (Society of Automotive Engineers) classification, which is based on the viscosity of oils at 100 ºC, presenting two scales: one of low temperature (from 0W to 25W) and another of high temperature, where we have lubricants going today (from 16 to 60). The letter "W" means "Winter" (winter, in English) and it is linked to the number before the letter W, that is, the first number of the set, expressing the viscosity of the lubricant in cold (cold engine). The higher this number, the higher this viscosity with the engine still cold. Smaller degrees withstand low temperatures without solidifying or impairing the pumping performed by the oil pump.

A mono-grade type oil can only be classified into one type scale. An oil with a higher viscosity index, on the other hand, can be classified in both temperature ranges, since it has a lower viscosity variation due to temperature changes. In this way, a multigrade oil, SAE 5W-30 for example, behaves at low temperature like a 5W oil, reducing wear when starting the engine still cold, and at high temperature it behaves like an SAE 30 oil, thus having a temperature range in its range of use.