Non-Detergent and Ashless – What does it all mean?
Detergent additives are used in some metalworking fluids, industrial lubricants and greases, but they are most widely found in engine oils today. Detergent additives keep metal components free of deposits and neutralize acids formed by oxidation or combustion products, they provide engine cleanliness and protect against rust and corrosion.
Additive usage in lubricants began in the 1930s to lubricate complex engines. Early automotive engine oils did not have detergent additives. Varnish and wear debris dropped out of the oil coating engine components. The first detergent engine oils were developed in the 1940s allowing deposits to be held in suspension in the oil and removed by the filtration system. Detergent engine oils contributed to cleaner engines and longer oil drain intervals.
When OEMs specify in their manuals “Use non-detergent SAE viscosity grade oil or equivalent” they are typically looking for an oil with anti-wear (AW) properties. Depending on the application, an oil with rust and oxidation (R&O) inhibitor additives might be a better option. Consider Hydrex, Compro, or Turboflo depending on the component the customer is lubricating.
Detergent additive chemistries contain metals typically calcium, magnesium, and sodium. Metal compounds when burned in oil leave an ash deposit. Ash is derived from metals found in additive chemistries, mainly detergent and anti-wear additives, as well as solids – including calcium, zinc and molybdenum. One of the most widely used anti-wear additives used in automotive and industrial oils is zinc dialkyldithiophosphate (ZDDP). ZDDP contains the metallic additive zinc, which upon combustion generates ash.
Ashless industrial oils are lubricants formulated without metallic additives. Rust and oxidation inhibited circulation oils, hydraulic oils formulated with anti-wear additives that are zinc free and food grade oils.
The definition for engine oils is quite different, Ashless engine oils are limited to an ash content of less than 0.01wt %.