LO 10-3 Identify and describe the purpose and function of oil additives

1.4. Oil Additive Categories

Oil Additive Categories

Technicians, as well as fleet and service managers, are frequently approached by product representatives promoting the use of aftermarket oil additives. It is important that these products be critically evaluated before they are used to avoid potentially severe economic consequences. Note too that aftermarket oil additives go through no standardized testing except by the U.S. Environmental Protection Agency (EPA) to certify that they are not toxic. An EPA test does not support any additive performance claim made by an additive maker. Common aftermarket oil additives and problems associated with each include the following:

• Products that are simply heavier-viscosity oil or additional VI additives that can reduce oil consumption. In the latest engines, more VI additives not only increase fuel consumption but also potentially starve bearings of circulating oil in much narrower oil clearances.
• Products containing polytetrafluoroethylene (PTFE), otherwise known as Teflon ® , mixed with high-viscosity motor oil. This powdery substance was claimed to be capable of coating engine parts with a protective film to reduce friction. However, a substantial body of evidence indicates that PTFE additive dumped into engine oil can in fact plug filters and small internal oil passageways. Many other tests and studies have demonstrated that PTFE additives actually increase engine wear.
• Products containing regular engine oil, including standard additives with the addition of zinc dialkyldithiophosphate (ZDDP). This zinc compound is added to many oil products already as an extreme pressure additive to minimize damage when metal-to-metal contact occurs. ZDDP must be kept to minimal values; field testing of engines with excess additive has found that the intermediate copper layer of bearings is often corroded through galvanic reactions when extra zinc is added to the engine oil.
• Products containing the same additives already used in major brands of oil but in different quantities and combinations. Engine-industry experts object to the use of these additives because they can disturb the delicate balance between base stock oil and additives already contained in the certified oil. Unintended chemical reactions can take place between these additional additives and the engine parts or additives already in the oil.