TBN Article - Whitepaper

When selecting your engine oil, there are many things to consider due to the fact that oils must function well to lubricate, cool and clean the engine. Total Base Number (TBN), is a property that measures oil’s ability to neutralize acids formed during engine operation. Generally, oils with a higher TBN better neutralize acidic materials and combustion by-products resulting in longer oil life and improved protection against corrosion.  Since TBN measurements are typically used as an indicator of the lubricants capacity to neutralize acids, they are especially useful when operators want to extend their drain intervals.

Diesel engine oils are normally formulated with a higher TBN to protect against the formation of acids caused by incomplete fuel combustion. The TBN of fresh oil is typically in the range of 7 to 10 for gasoline engines and 10 to 14 for diesel engines. If the TBN drops to a point where the oil can no longer neutralize acids, usually around 3 -or- half of its starting number (OEMs vary in what they recommend), the oil should be changed.

The most common cause for a TBN drop is oil oxidation. Oil oxidation occurs naturally over time and can commonly be observed in extended drain interval situations. Oxidation is also related to high operating temperatures.  Oils exposed to higher operating temperatures, especially engine overheating, oxidize more quickly. Another cause of a dropping TBN result is the use of low-quality fuel with high levels of sulfur. Sulfuric acid formed during the combustion process is neutralized, leading to a corresponding drop in TBN. 

TBN is just one of many engine oil parameters important to engine durability and extended service intervals. The best way to test if your lubricant is providing adequate acid neutralization is with oil analysis.  As part of a routine maintenance program, oil analysis can help establish safe and proper drain intervals.  Tests of the used oil’s physical properties can identify wear metals or contaminants like antifreeze or dirt before any permanent damage is done. The price of oil analysis is included in the purchase of Archer Lubricants.

Contact your local Archer Lubricants distributor for information on how engine oil analysis can work for you and how Archer Premium Arpeco is formulated to protect against corrosive acids well throughout the drain interval using a unique detergent package.  You will rest easier knowing that you are establishing change intervals that reduce unforeseen issues, breakdowns, and downtime while extending equipment life.  You’ll also be confident that today’s lower viscosity oils that improve fuel economy are continuing to provide the wear protection you need.