What are the main functions of oils?

  • Prevent abrasion and friction in the systems (by creating a film layer between the running system)
  • Remove heat from the environment
  • Keep the system clean thanks to its detergent dispersant feature
  • Move dirt and sediment in the systems to the filters and protect them against rust and corrosion
  • Insulate the systems against external factors

Why is lubrication necessary?

  • It should be performed to reduce friction.

What is friction?

  • Physical interaction between metals
  • The friction of parts rubbing against one another causes heat
  • Heated parts expand, and their ends touch and break
  • Wear particles work like cutting tools. Scratches, vibration and heat increase.

What is viscosity?

  • Viscosity is a measure of a liquid's resistance to flow and shown in mm²/s or centistoke (cSt).

What is viscosity index?

  • It describes the behavior of a liquid's viscosity in response to temperature change. The viscosity index of oils that are easily affected by temperature changes is low.

How is viscosity classified? (Engine Oils and Automotive Gear Oils)

  • Decisions on engine oils and automotive gear oils are made by SAE (Society of Automotive Engineers) based on the viscosity value at 100 ºC and low temperature pumpability test results.

How is viscosity classified? (Industrial Oils)

  • Industrial Oils are classified by ISO VG (International Organization for Standardization) based on their 40 ºC viscosity value. For example, a hydraulic oil numbered 46 will be classified with a tolerance value of +/- 10%.

How are greases classified based on penetration?

  • Penetration is measured in the testing device specified in ASTM D-217. It is a numerical value that indicates whether the grease is hard or soft.

Classification of NLGI Grease Penetration

  • The higher the NLGI penetration value is, the harder the grease becomes.

What is grease?

  • It is used on surfaces that liquid oils have difficulty adhering to under extreme load and pressure, and is effective thanks to the additives it contains. It is generally used for lubricating most bearings and rollers.

What is the pour point?

  • The lowest temperature at which a liquid drips at its own weight is called the pour point (e.g. -27°C)

What does a low pour point mean?

  • It ensures easy pouring at low temperatures.
  • It ensures that liquids maintain their fluidity at low temperatures and that the systems operate easily during the first start-up.
  • It indicates pumpability.

What is the dropping point?

  • It is the temperature at which the grease transforms from a semi-solid to a liquid under test conditions and is one of the most important indicators of the heat resistance of the grease (e.g. 240°C)

What is a flash point?

  • It is the lowest temperature at which flammable liquids emit a sufficient amount of vapor to be ignited by the air at their immediate surface.

What is TBN?

  • Total Base number: The amount of KOH required to neutralize a petroleum product. It is used to neutralize the acidic environment that occurs as a result of the reaction in diesel vehicle engine oils. It is of vital importance for the system.


  • are generated by distilling and refining petroleum.

Synthetic oils

  • are oils that have been adapted to the desired properties by chemical synthesis.

What are the differences between lubricants and synthetic oils?

  • Synthetic oils have superior power transmission, a more stable film layer under heavy loads, better pumpability at low temperatures and higher energy savings compared to lubricants.

Information about antifreeze

  • It is typically colorless and transparent
  • Before adding water to the radiator, water should first be mixed with antifreeze water
  • Antifreeze and pure water should be mixed at a ratio of 50%.
  • The antifreeze level should be checked periodically.

Functions of antifreeze

  • To prevent water from freezing,
  • increase the boiling point
  • prevent calcification,
  • protect the system against corrosion,
  • increase the boiling point and prevent cavitation