HOW IS MOTOR OIL LIFETIME MEASURED?

Many newest generation passenger car and heavy-duty commercial engine lubricants provide long-lasting active protection to your engine component, resulting in oil drain intervals for European vehicles as high as 30,000 kilometers/two years (whichever comes first) for passenger cars and 120,000 kilometers for trucks. Protecting the components from damage, such as that caused by corrosive and wear, keeps engines operating at maximum efficiency for as long as possible, enabling the lowest emissions and highest fuel conserving possible, and keeping operating costs as low as possible.

Keeping track of lubricant lifetime is a key consideration for maintaining engine durability. As the engine lubricant ages in service, contaminants build up in the lubricant and the lubricant’s physical properties change, which can harm the lubricant’s performance. Used oil analysis is commonly utilize to evaluate the lubricant life in vehicles. Typical parameters measured by UOA include wear metal content, oxidation and nitration of the lubricant, viscosity change, soot content, and buildup of acid.

Measuring TAN and TBN is used to quantify the build-up of acids in the engine lubricant. These acids form as a result of the fuel combustion process and the degradation of the engine lubricant under the harsh operating conditions inside an engine. At the beginning of an oil drain interval the TAN will be low and the TBN will be high. Over the course of an ODI, TAN will increase as the acidic contaminants accumulate, while TBN will decrease as the active base content of the lubricant is consumed. Historically, the point at which TAN increases above TBN – the “TBN/TAN crossover” – was considered to be the point at which the lubricant had reached the end of its useful life.