Is SAE 30 the same as 30w

The meaning of '5W30': What does the SAE specification mean?

Every engine oil has such a designation printed on it: This is something like '5W30', '10W40', '5W40' or other information. What these numbers mean exactly is explained in this article.

At the end the meaning of '5W-30' is explained.

What does the SAE specification mean in general?

The designation '5W30' etc. is the so-called SAE classification. These are viscosity classes (= measure of the viscosity) that have been officially established since 1911. You can say that it is an indication that divides the oil into classes of different flow behavior.

This means how viscous an oil is at a certain temperature. You can think of an engine oil a bit like honey: if the oil is very cold, it is very solid and hardly flows. On the other hand, if you bring it to high temperatures, it becomes very fluid and flows very easily.

The following applies: the smaller the number, the more fluid the oil is.

Why does the information consist of two numbers (in the form 'xxW-yy‚)?

The next logical question is why the SAE specification consists of two numbers. The answer to this is simple: it has historical reasons.

Today's oils, which have two numbers (in the form such as ’10W-40 ′), are multigrade oils. However, this did not exist before. At the beginning of the introduction of the SAE classification, the oils were divided into summer and winter oils. These are either only suitable for summer or only for winter operation. The 'W' means 'winter'.

If you come across an oil whose SAE specification consists of only one number, this is a so-called single grade oil. For example, an oil of the 'SAE 80' class would only be suitable for summer operation. If the designation is only 'SAE 80W', then it is only suitable for winter operation.

Modern engine oils today are designed in such a way that they are suitable for both winter and summer operation. These multigrade oils therefore carry the information for both summer and winter operation.

The meaning of '5W30'

As we now know, the first number in front of the 'W' indicates the low-temperature viscosity (lowest viscosity). The number after that is the high temperature viscosity (highest viscosity).

The meaning of 5W-30 as follows:

  • SAE 5W (Low temperature viscosity): The lowest temperature at which the oil can still be pumped under specified conditions −35 ° C
  • SAE 30 (High temperature viscosity): The minimum viscosity at 100 ° C is 9.3 mm2 / s

The individual values ​​can be found in the viscosity table.

Specifically, the 5W-30 oil is a low-viscosity oil that is usually offered with long oil change intervals. In accordance with its temperature, it behaves thinly enough for good lubrication in the cold and not too thinly liquid at high temperatures to build a stable lubricating film.

Like every multigrade oil, the effect in practice is that its viscosity does not change as much at different temperatures as would be the case with single-grade oils. Therefore, a multigrade oil can be used all year round, with relatively constant flow behavior. For example, starting the engine is made easier in winter and the engine is lubricated faster.

More information on classification and specification.