Oil Types Information

Here is the "not too technical, technical enough but still correct" answer to your question. To most people, oil is oil; oil is a lubricant, first and foremost. However, even if we ONLY deal with motor oil, there are many different brands, classifications, types and grades, synthetic and conventional; what is right for one engine is not necessarily right for another.

Motor oil must perform two entirely different duties inside your engine, do them both reasonably well, and do them under conditions of vastly different temperature ranges. Obviously, the main job of oil is to reduce friction, thus eliminating or at least reducing, engine components wear and tear. Due to basic engine design, oil stays in the engine at contact points because of rings, valves, gaskets and seals. Oil helps to both lubricate and seal those objects. One of the qualities of oil is viscosity, how thick or thin it is. That quality changes with temperature, getting thin at higher temperatures (low viscosity) and thicker at low temperatures (high viscosity); too think or too thin is not good. As you might perceive, low viscosity oil and lubricants flow with relative ease; an example for comparison only, might be the ease of baby oil in pouring or spreading it. In contrast, higher viscosity oil might be compared to honey; it does not pour quite so easily. The higher the viscosity number (explained later), the thicker the oil. Are there advantage and disadvantages to both? Yes... Though in reality, they must be carefully considered as a sum of benefits and liabilities and as a whole, which product is best for your driving needs and surrounding environment.

There are three foundational types of oil, regular (light use), premium (some hard use, such as stop and go, AND highway driving) and heavy duty (for the toughest and extreme conditions), as defined by the American Petroleum Institute, or API for short. To further classify and define the duty of the oil, there are some additional API designations to "code" the oil for service classifications. (You can see all of these codes on a can or bottle of oil when you shop for it.) There are two of those general groups, of which S stands for Standard Service (Spark ignited), used in gasoline engines, and C stands for Commercial Compression (Compression ignited), used in diesel engines. Within each of those groups, several additional qualifiers designate the varieties and qualities of Standard Service duty oil; they are designated by also a letter applicable for either S or C general groups. The most common S quality qualifiers are:

SA - This is the designation of a plain mineral oil that contains none of the modern additives common currently in lubricants. The SA (only) designation was made obsolete in the 60s.

SB - Lubricating oils that contain anti-wear, anti-oxidation and anti-corrosion inhibitors. This was an early attempt at a moderate to severe conditions oil but is more or less antiquated as of the early 70s, though still the used and sold version of non-detergent oil if that is specified by a manufacturer. Considered now as specific use minimum duty. SC - A time mandated replacement for the SB classifications and ratings, though not a direct replacement for SB due to changing to detergent. It is also now obsolete.

SD - A time mandated replacement for the SC classifications, also now obsolete.

SE - A time mandated replacement for the SD classifications, also now obsolete. This classification offered more protection than the SD group of lubricants and was suitable for extreme and severe use duty applications. This superceded SD but is now also obsolete.

SF - Recommended for late 70s, 1980 - 1989 passenger vehicles. This oil had excellent anti-wear properties and greatly improved anti-oxidation stability over SE lubricants. It is now obsolete.

SG - The SG rating was introduced in 1989 and combined SF with the performance properties of the commercial rating CC (lubricants designed for use in supercharged/turbocharged diesel applications in moderate to severe service). It is also now obsolete.

SH - This superceded SG and was designed for 1996 and older engines. It is now obsolete.

SJ - Introduced in 1996, this rating is still available for all automotive engines currently in use.

SL - Introduced in 2001, SL provides improved overall performance for 2002 model year vehicles, including greatly enhanced anti-oxidation properties, low temperature viscosity as well as other beneficial properties. Also current and does cover all of the SJ qualifications.

For C (Commercial diesel applications), the quality qualifier designations are the same but the popular current ratings are:

CC - Commercial light duty use of diesel engines, such as passenger vehicle engines, with or without supercharger or turbochargers on them.

CF - Designed for use in heavy off road work applications of diesel engines.

CF2 - Designed for use in heavy 2 cycle diesel engines.

CF4 - Designed for use in heavy 4 cycle diesel engines.

Oil and lubricant manufacturers rate the viscosity of the oils. They have single and multi-grade products for motor oils. For instance, a single grade "average motor oil" is SAE 30. An average multi-grade oil is SAE 10W-30. SAE is the abbreviation for the Society of Automotive Engineers, the rating organization for viscosity. That SAE designation is usually followed by a number and a letter. This indicates the uniform viscosity of the oil, such as SAE - 30W. In the case of multi-viscosity oils, such as SAE - 10W 30, (often called multi-grade), the first number is the viscosity at the lowest end (coldest) of the temperature range while the second number is for the highest (warmest). The letter W stands for WINTER, (indicating the viscosity at the cold end of operating range). That is a good guideline, but to complicate matters, the temperature scale is NOT the same for each viscosity code. My advice is to use the lubricants recommended in your vehicle's owner's manual.