How Important Is Viscosity in Engine Oil?

Viscosity or kinematic viscosity--the resistance of a liquid to flow--is one of the most important characteristics of engine oil. The viscosity of engine oil must be sufficient to lubricate the moving parts of an engine at normal operating speeds and temperatures.

  1. Function

    • The function of engine oil is to reduce friction and wear and tear on engine components, particularly engine pistons. Too thin oil can cause permanent leaks in the engine seals, while too thick oil can lead to high operating temperatures and difficulty starting an engine in cold weather.


    • Viscosity is the result of internal, molecular friction within engine oil. The greater the friction the greater the viscosity and the greater the load the oil can withstand.


    • Kinematic viscosity of engine oil is commonly measured in centistockes (cSt) or Saybolt Universal Seconds (SUS) at a given temperature. In this case, the higher the number the higher the viscosity or thickness of the oil.

Related Searches


You May Also Like

  • What Is Oil Viscosity?

    Oil is rated by the Society of Automotive Engineers (SAE) for viscosity. Viscosity is a rating which describes the thickness of a...

  • How to Test Oil Viscosity

    Viscosity is an important aspect for oil used in machines and transportation vehicles. Viscosity is defined as how the oil flows as...

  • How to Read Oil Viscosity

    Motor oil viscosity, or thickness, is given by an alpha-numeric code on the can. This code describes how thick the oil is,...

  • Oil Viscosity vs. Temperature

    Choosing the right oil viscosity grade for your vehicle requires consideration not only of viscosity, but also of the temperatures in which...

  • Recommended Oil Viscosity for High Mileage Oil Leaks

    Any car, especially as it accrues more mileage, is susceptible to oil leaks and consuming oil. However, there are a few tricks...

  • Why Change the Oil in a Car?

    Comments. You May Also Like. Why It's Important to Change Your Car's Motor Oil. When changed regularly, oil helps a car run...

  • Definition of Oil Viscosity

    Oil viscosity refers to how thick, or heavy, oil is. The oil viscosity is often used to describe different types of oil...

Related Ads

Related Searches
View Photos

10 Fun Ways To Spend Your Tax Refund