Oil additive

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Oil additives are used to improve the base oil (or oil "base stock") into a better performing lubricant. By utilizing the same base stock, many different oils can be manufactured, each with its own unique properties.

Nearly all motor oils currently being sold have an additive package, whether they are synthetic or petroleum based. Essentially, only API Service SA motor oils have no additives whatsoever, and they are therefore incapable of protecting modern engines. Different additives are used depending on the application, e.g. the oil for a direct-injected diesel engine in a pickup truck (API Service CJ-4) has different additives than the oil used in a small gasoline-powered outboard motor on a boat (2-cycle engine oil).

According to a source in the petroleum industry,

"A lubricant additive package can comprise anywhere from 1% of a finished hydraulic oil to approximately 20% of a typical multi-grade motor oil."

Types of Additives

• Detergent additives, dating back to the early 1930s, are used to clean and neutralize oil impurities which would normally cause deposits (or sludge) on vital engine parts.
• Friction modifiers, like molybdenum sulfide, are used for increasing fuel economy by reducing friction between moving parts.
• Viscosity modifiers make an oil's viscosity lower for cold starts. Multi-weight oils all have viscosity modifiers.
• Deposit control additives prevent the formation of soft sludge and hard deposits of impurities.
• Corrosion or oxidation or rust inhibiting additives retard the oxidation of metal inside an engine.
• Antioxidant additives retard the decomposition of the stock oil.
• Antiwear additives or wear inhibiting additives cause a film to surround metal parts, helping to keep them separated.
• Pour point depressants improve the oil's ability to flow at lower temperatures.
• Anti-foam agents inhibit the production of air bubbles and foam in the oil which can cause a loss of lubrication, pitting, and corrosion where entrained air contacts metal surfaces.
• Seal conditioners cause gaskets and seals to swell so that the oil cannot leak by.
• Metal deactivators create a film on metal surfaces to prevent the metal from causing the oil to be oxidized.
• Extreme pressure agents bond to metal surfaces, keeping them from touching even at high pressure.
• Dispersants cause contaminants (e.g. soot) to be suspended in the oil to prevent them from coagulating.
• Wax crystal modifiers are dewaxing aids that improve the ability of oil filters to separate wax from oil.

Additives in the Aftermarket and Controversy

Although motor oil is manufactured with numerous additives, aftermarket oil additives exist, too. A glaring inconsistency of mass-marketed aftermarket oil additives is that they often use additives which are foreign to motor oil. On the other hand, commercial additives are also sold that are designed for extended drain intervals (to replace depleted additives in used oil) or for formulating oils in situ (to make a custom motor oil from base stock). Commercial additives are identical to the additives found in off-the-shelf motor oil, while mass-marketed additives have some of each.

Some mass-market oil additives, notably the ones containing PTFE/Teflon (e.g. Slick 50) and chlorinated paraffins (e.g. Dura Lube), have caused a major backlash by consumers and the U.S. Federal Trade Commission which investigated many mass-marketed engine oil additives in the late 1990s. Although there is no reason to say that all oil additives used in packaged engine oil are good and all aftermarket oil additives are bad, there has been a tendency in the aftermarket industry to make unfounded claims regarding the efficacy of their oil additives. These unsubstantiated claims have caused consumers to be lured into adding a bottle of chemicals to their engines which do not lower emissions, improve wear resistance, lower temperatures, improve efficiency, or extend engine life more than the (much cheaper) oil would have. Many consumers are convinced that aftermarket oil additives work, but many consumers are convinced that they do not work and are in fact detrimental to the engine. The topic is hotly debated on the Internet.

Although PTFE, a solid, was used in some aftermarket oil additives, users alleged that the PTFE clumped together, clogging filters. Certain people in the 1990s have reported that this was corroborated by NASA and U.S. universities. One thing to note, in defense of PTFE, is that if the particles are smaller than what was apparently used in the 1980s and 1990s, then PTFE can be an effective lubricant in suspension. The size of the particle and many other interrelated components of a lubricant make it difficult to make blanket statements about whether PTFE is useful or harmful. Although PTFE has been called "the slickest substance known to man," it would hardly do any good if it remains in the oil filter.

See also

• Oil analysis
• Fuel additive

External links

• The American Chemistry Council's Petroleum Additives Panel link to oil additive manufacturers.
• List of oil additives for passenger cars and what they do.

References

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Last updated on Friday July 18, 2008 at 11:01:16 PDT (GMT -0700)
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