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Engine oil Viscosity and Grading

Engine oil Viscosity and Grading

Motor Oil Viscosity

Oil viscosity is the characteristic and ability of an oil to flow smoothly into the engine at a certain temperature. Talking about the types of engine oil, engine oil is of two types. On the one hand, there is thin oil and on the other hand, there is thick oil. Thin-oil has low viscosity while thick oil has high viscosity. The low viscosity of thin oil helps the oil to resist friction and the thick viscosity help the oil to keep the pressure in check. Unless the motor oil has a perfect balance viscosity, there is no way that it is going to work fine in a motor.

In case the oil viscosity is not balanced then the driver can get into all sorts of troubles. For instance, if thin motor oil has very low pressure then it won’t be able to flow easily through different parts of the engine. This would increase the friction and this way the components of the engine will wear off. Same, if the oil is too thick then it is not suitable for the engine because the thickness of the oil will not allow the oil to flow into the smaller components. This would result in the damaging of the engine and its components. 

How to measure Oil Viscosity?

It is very simple to measure oil viscosity. Oil viscosity is measured on the basis of two units which are centipoise and centistoke. 

Centipoise is the unit which depicts the movement of the different layers of oil under the horizontal force.

Centistoke measures the capability of oil to flow under the influence of gravity. To measure viscosity these two units can assist brilliantly.

Grading of Engine Oil

Grading of engine oil is no rocket science. For the grading of engine oil, an international standard scale is used. This particular scale has been developed by the society of automotive engineers. The scale is called QW-T. 

QW-T Q stands for the viscosity of the engine oil at low temperatures. W stands for the particular engine in which oil has been tested at low temperatures. T stands for the viscosity of the engine oil at high temperatures when the engine is running. By reading this amazing scale one can perfectly and easily determine the right engine oil.

As far as the grading of engine oils is concerned that there are 11 different gradings of viscosity in engine oils.

  • 0W means the rating of 0 thickness at winter temperature.
  • 5W means the rating of 5 thickness at winter temperature.
  • 10W means the rating of 10 thickness at winter temperature.
  • 15W means the rating of 15 thickness at winter temperature.       
  • 20W means the rating of 20 thickness at winter temperature.
  • 25W means the rating of 25 thickness at winter temperature.
  • 20 means the rating of 20 thickness at a warm temperature.