Petroleum Quality Institute of America

The Petroleum Quality Institute of America (PQIA) is an independent resource for information and insights on the quality and performance of lubricants in the marketplace.  Our mission is to serve the consumer of lubricants by reporting on the quality and integrity of lubricants in the marketplace.   




Additives are used in engine oils to prevent formation of sludge. These additives are commonly referred to as detergent-dispersants. Dispersants are typically a high--molecular weight nitrogen containing compound that encircle the by-products of combustion and keep them in suspension until they can be removed through filtration and/or an oil change. Nitrogen is also contained in some anti-oxidants which control oxidation. This can also be very beneficial to the oil. 

The level of nitrogen in an engine oil is generally an indicator of the dispersancy characteristics of the oil.  Like all performance areas, however, formulations must be well balanced and  certain sources of nitrogen can negatively impact seals. In other words, whereas too little nitrogen suggests concerns about performance, too much can also be reason for concern. 

It's important to note there are other chemicals that can be added to an engine oil to boost the nitrogen level (and present a typical profile), but, some of these chemicals can be harmful to the engine. Whereas they artificially provide nitrogen levels commonly seen in an engine oil, they may not provide the functionality of dispersants and  anti-oxidants. As such, it's important to keep in mind that too little nitrogen can be as concerning as too much.










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