What Are the of Air Compressor Oil Types? Which One is Better?

Air compressor oil and types are critical component in ensuring the efficient operation and longevity of compressors. Understanding the role of lubricating oil in air compressors and its importance can help users maintain their equipment more effectively.

Role of Lubricating Oil in Air Compressors

Reducing Friction and Wear

The primary function of lubricating oil in air compressors is to minimize friction between moving parts. Components such as pistons, bearings, and rotors move at high speeds, generating significant friction.

Lubricating oil forms a film between these parts, reducing direct contact, which in turn decreases wear and tear. This prolongs the lifespan of the components and ensures smoother operation.


Air compressors generate a considerable amount of heat during operation. Lubricating oil helps in dissipating this heat away from critical components.

By absorbing and transferring heat, the oil prevents overheating, which can lead to equipment failure or reduced efficiency.


How to Prevent Compressor Overheating? Ultimate Solutions

Compressor overheating is a common problem that can adversely affect the performance of the equipment and even lead to complete breakdown.

So, what unfavorable factors will cause it to overheat, and what are the solutions to prevent the compressor from overheating?


In many air compressors, especially in rotary screw and vane compressors, lubricating oil also plays a role in sealing. It helps in creating a tight seal in the compression chamber, preventing air leakage and ensuring efficient compression.

Sealing action can enhance the overall efficiency of the air compressor by maintaining the desired pressure levels.


In addition, lubricating oil assists in keeping the internal components of the air compressor clean. It picks up contaminants and particles generated during operation and carries them to the oil filter, where they are removed from circulation.

The cleaning process prevents the buildup of debris that can cause blockages and reduce the efficiency of the compressor.

Rust and Corrosion Prevention

Another critical role of lubricating oil is to protect internal components from rust and corrosion. By coating metal surfaces, the oil creates a barrier that prevents moisture and corrosive substances from causing damage.

So, What Are the Types of Air Compressor Oil?

Mineral Oil and Synthetic Air Compressor Oil

Requiring proper lubrication to function efficiently and extend air compressor lifespan. Two primary types of air compressor oil are commonly used: mineral oil and synthetic oil. Each has unique properties and advantages, catering to different operational needs and conditions.

Mineral Oil

Mineral oil is derived from refining crude oil. It is the traditional choice for lubricating air compressors and has been widely used due to its cost-effectiveness and availability.

Properties and Benefits

1. Cost-Effective

One of the main advantages of mineral oil is its affordability. It is less expensive compared to synthetic oil, making it a popular choice for applications where budget constraints are a concern.

2. Adequate Performance

Mineral oil provides sufficient lubrication for most standard air compressor applications. It performs well under moderate temperatures and pressures.

3. Compatibility

Mineral oil is compatible with most air compressor components and seals, reducing the risk of chemical reactions or material degradation.


1. Shorter Lifespan

Mineral oil tends to break down faster than synthetic oil, especially under high temperatures and heavy loads. This requires more frequent oil changes

2. Performance in Extreme Conditions: Mineral oil may not perform optimally in extreme temperatures, whether hot or cold, which can affect the efficiency and longevity of the compressor.

Usage Recommendations

Mineral oil is suitable for light to moderate duty air compressors used in workshops, small manufacturing units, and similar settings.

Synthetic Air Compressor Oil

Synthetic oil is chemically engineered to provide superior performance compared to mineral oil. It is designed to withstand extreme conditions and offer enhanced lubrication properties.

Properties and Benefits

1. Extended Lifespan

Synthetic oil has a longer service life compared to mineral oil. It can withstand higher temperatures and pressures without breaking down, resulting in fewer oil changes and reduced maintenance costs.

2. Enhanced Performance

This type of oil provides better lubrication, reducing friction and wear on the compressor’s moving parts. This leads to improved efficiency and a longer lifespan for the compressor.

3. Temperature Stability

Synthetic oil remains stable across a wide temperature range, making it ideal for compressors operating in extreme hot or cold environments.

4. Cleaner Operation

Synthetic oil tends to produce fewer deposits and sludge, keeping the compressor’s internal components cleaner and functioning more smoothly.


1. Higher Cost

The primary drawback of synthetic oil is its higher cost compared to mineral oil. However, the longer intervals between oil changes and enhanced performance can offset this initial expense over time.

2. Compatibility Concerns

In some cases, synthetic oil may not be compatible with older compressors or certain seal materials. It is essential to check the manufacturer’s recommendations before switching to synthetic oil.

Usage Recommendations

Synthetic oil is ideal for heavy-duty industrial air compressors used in demanding industrial applications, such as manufacturing plants, automotive workshops, and continuous operation environments.

It is particularly beneficial where compressors are subject to high temperatures, heavy loads, or require extended running times.

What is Air Compressor Oil Number?

The air compressor oil number usually represents the oil viscosity grade.

One of the critical aspects of air compressor oil is its viscosity grade, which ensures that the oil performs well under operating conditions.

What is the Meaning of Oil Viscosity Grade?

Oil viscosity grade is a measure of an oil’s resistance to flow at a specific temperature. The term “ISO VG” stands for International Standards Organization Viscosity Grade, which is a standard for categorizing industrial oils based on their viscosity at 40°C, measured in centistokes (cSt).

Understanding Viscosity


This refers to the thickness of the oil or its resistance to flow. Higher viscosity means thicker oil, while lower viscosity means thinner oil.

ISO VG Classification

Oils are classified into grades such as ISO VG 32, ISO VG 46, and ISO VG 68, among others. The number indicates the viscosity at 40°C.

For instance, ISO VG 46 oil has a viscosity of 46 cSt at 40°C.

Importance of Viscosity Grade

Lubrication Efficiency

The correct viscosity ensures proper lubrication of moving parts. If the oil is too thin (low viscosity), it may not provide adequate film strength, leading to increased wear.

Conversely, if the oil is too thick (high viscosity), it may not flow easily, causing inadequate lubrication and increased energy consumption.

Temperature Adaptability

Oils with the appropriate viscosity grade maintain their performance across the expected temperature range of the air compressor. This adaptability is crucial for preventing overheating and ensuring smooth operation.

What Grade of Lubricating Oil Recommended for Screw Air Compressors?

Screw air compressors require specific lubrication to handle their high operational demands. The most commonly recommended grade for these compressors is ISO VG 46.

Why ISO VG 46?

Optimal Balance

ISO VG 46 offers an optimal balance between fluidity and film strength, providing effective lubrication under the typical operating conditions of screw air compressors.

Temperature Stability

This grade performs well across a range of temperatures, ensuring that the oil remains effective in both moderate and high-temperature environments.

Manufacturer Standard

Most manufacturers recommend and use ISO VG 46 oil for screw air compressors when they leave the factory. This standardization helps ensure the compressors operate efficiently and have a longer service life.

Benefits of Using the Recommended Oil Grade

Reduced Wear and Tear

Proper lubrication reduces friction between moving parts, minimizing wear and tear and extending the compressor’s lifespan.

Improved Efficiency

Using the correct oil grade ensures that the compressor runs smoothly, reducing energy consumption and improving overall efficiency.

Lower Maintenance Costs

Adequate lubrication prevents common issues such as overheating and component failure, to reduce the need for frequent repairs and maintenance.


What is the Best Oil for Rotary Screw Compressor?

Choosing the right oil for rotary screw compressor is crucial for maintaining its performance, efficiency, and longevity. The type of oil used can significantly impact the operation and maintenance requirements of the compressor.

Air Compressor Oil Type Chart

Type of Lubricant Description Recommended Usage
Mineral Oil Derived from refining crude oil. Cost-effective and provides adequate lubrication for standard applications. Suitable for light to moderate duty air compressors in workshops, small manufacturing units. Requires frequent oil changes.
Synthetic Oil Chemically engineered for superior performance. Longer lifespan, better temperature stability, and fewer deposits. Ideal for heavy-duty air compressors in demanding industrial applications. Reduces maintenance costs and extends equipment lifespan.
ISO VG 46 Lubricating Oil Viscosity grade at 40°C with 46 centistokes. Offers optimal balance of fluidity and film strength. Recommended for screw air compressors. Ensures efficient operation and longer service life, standard for many manufacturers.

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