Lubricant additives have three basic roles:

  • Enhancing existing base oil properties with antioxidants, corrosion inhibitors, anti-foam agents and demulsifying agents.
  • Supressing undesirable base oil properties with pour-point depressants and viscosity index improvers.
  • Imparting new properties to base oils with extreme pressure additives, detergents, metal deactivators and tackiness agents.

There are many types of chemical additives mixed into base oils to enhance their properties. Additives typically range between 0.1 to 30% of the oil volume, depending on the target application of the lubricant. Creating the proper mix of additives is a complicated science, and it’s the choice of additives that differentiates a turbine oil from a hydraulic oil, a gear oil and an engine oil.

Lubricant additives are selected by manufacturers for their ability to perform a specific function, their ability to mix easily with the base oil, to be compatible with other additives in the formulation and to be cost effective. Some additives perform their function within the oil (e.g. anti-oxidants), while others work on the surface of the metal (e.g. anti-wear additives).

When using oil additives, more is not always better. As more additive is blended into the oil, sometimes there isn’t any more benefit gained, and sometimes performance deteriorates. While an additive may improve one property of the oil, it could have a negative impact on another property, causing the overall performance of the lubricant to be affected.

There are also numerous after-market additives and supplements available on the market. Some of these have their place in certain applications, but many make unproven claims or neglect to mention the negative side effects they cause. Take great care in the selection and application of these products, or better still, avoid using them. Buying a better oil in the first place is usually the best option.

For more information on the types of lubricant additives available, read the full article at