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What viscosity is compressor oil?


Air compressors require a dedicated lubricant designed specifically to answer the operational challenges and equipment requirements of this type of equipment. While this product is known simply as an air compressor oil different viscosities are available. In this blog, we’ll study air compressor oil and look at its viscosity in greater detail.

What makes compressor oil different from engine oil

Air compressor oils have specific additive packages that make them perfect for work inside air compressors. In contrast to standard engine oil, which is more widely known, air compressor oil does not contain any detergent and usually has far lower levels of carbon and sulphur.

Different levels of viscosity

Air compressor oil viscosity is sometimes referred to by different terms like “air compressor oil type” and “air compressor oil grade”. Since the emergence of modern lubrication viscosity levels in today’s oils tend to range between SAE 20 and SAE 30 range, however oils with more extreme viscosity remain available, but are seldom used in machine applications.

The same trend applies to air compressor oils. Both SAE 20 and SAE 30 oils are ideally suited for use with an air compressor. The difference between SAE 20 oils and SAE 30 oils for air compressors is not huge. In simple terms, SAE 20 is not quite as viscous. This means that at colder temperatures the compressor oil causes less drag on the air compressor allowing it to run slightly more effectively.

SAE 30 air compressor oil is more viscous. As a result, when operating at colder temperatures, its viscosity can be slightly higher than desired. With the impact being that the compressor will run a little less efficiently when running at colder ambient temperatures.

Compressor oil behaviour

It’s worth noting that as a compressor runs, heat generated during operation will effectively reduce the viscosity of SAE 20 and SAE 30 air compressor oils. However, in sustained use at lower temperatures, SAE 20 oil can outperform SAE 30 when it comes to efficiency.

In sustained use in operating temperatures which are higher or moderate, SAE 30 compressor oil will keep more of its lubrication properties than a number SAE 20 compressor oil. Under such conditions, SAE 20 compressor oil will possess sub-optimal viscosity, becoming thinner at a lower operating temperature than a SAE 30 air compressor oil would.

This distinction is important but only for equipment users who are operating their air compressor continuously or daily.


At Oil-Store, we stock a range of air compressor oils, available from top brands including CPI Fluid Engineering, Millers and Mobil. Shop the range today.

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