How to choose the right oil for your compressor

Just as a well-oiled machine runs smoothly, compressed air relies on the right oil for optimal performance and longevity. While not all compressors require oil, those that do depend on it as a vital lubricant, reducing friction and wear between moving parts. This crucial function ensures the compressor operates efficiently, reliably, and safely.

However, choosing the wrong oil can have a direct impact on your bottom line. It can lead to increased operational costs, unexpected downtime, and a shorter lifespan for your valuable equipment. This guide will explore the critical role of oil in your air compressor, delve into the different types available, and provide you with the knowledge to select the best oil to maximise performance and keep your business running smoothly.

How is Air Compressor Oil Different from Other Types?

Would you put cooking oil in your car engine? The same principle applies to air compressors. While it might be tempting to use alternative lubricants, standard oil or hydraulic fluid will cause significant damage to your air compressor systems.

Here’s why dedicated air compressor oil is essential:

Unique Formulation: Air compressor oil is specifically designed to withstand the high heat, pressure, and moisture present in compressor systems. Other oils lack these properties and will break down, forming harmful deposits.

System Compatibility: Using the wrong type of oil will lead to:

• Clogged oil circuits and filters.
• Damaged seals, leading to leaks and reduced efficiency.
• Increased friction and wear on vital components.

Operational Risks: Using an unsuitable oil compromises your compressor’s performance and lifespan, increasing the likelihood of:

• Premature component failure.
• Costly downtime and repairs.
• Reduced energy efficiency.

Choosing the correct air compressor oil is essential for ensuring the longevity, performance, and safety of your equipment.

Synthetic vs. Mineral Oil: Which is Right for Your Air Compressor?

Choosing the right oil type is essential for your compressor’s longevity and performance. Two main types of air compressor oil are available: synthetic and mineral-based oils, each with distinct benefits.

Synthetic Oil: Best for High-Performance Compressors

Synthetic oil offers superior protection, especially in extreme conditions. It performs exceptionally well in high temperatures and continuous operation, reducing friction and wear. With longer oil change intervals, it minimises downtime and maintenance costs. Although more expensive upfront, synthetic oil can save money in the long term by improving compressor efficiency and reducing wear on compressor parts.

However, it’s important to consult your compressor manufacturer’s recommendations before switching to synthetic oil, as some models may not be compatible.

Mineral Oil: Affordable for Less Demanding Applications

Mineral oil, refined from crude petroleum, is a cost-effective option for compressors operating in moderate conditions. It’s budget-friendly and widely available. However, it requires more frequent oil changes and is less effective in extreme environments, which can impact compressor performance over time.

Which to Choose?

For compressors that operate under heavy load or in extreme environments, synthetic oil is the best option. For lighter or intermittent use, mineral oil is a more affordable alternative. Always follow your compressor manufacturer’s recommendations to ensure the proper air compressor oil for your specific application.

Factors to Consider When Choosing Oil

Several other factors play a crucial role in ensuring optimal performance and longevity for your equipment. 

Compressor Type and Requirements

Different types of air compressor designs have varying lubrication needs. 

For instance, rotary screw compressors, known for their continuous operation and higher operating temperatures, typically require oils with excellent thermal stability and resistance to foaming. 

Reciprocating compressors, on the other hand, with their stop-start cycles, benefit from oils with strong wear protection and rust-inhibiting properties to protect against condensation. 

High-speed centrifugal compressors, meanwhile, often require specially formulated oils designed for high shear stability and to prevent foaming at high rotational speeds.

Always consult your compressor’s manual for specific oil recommendations tailored to your model. The manufacturer knows their equipment best and will provide guidelines to ensure optimal performance and longevity.

Viscosity Needs

Viscosity, simply put, is the oil’s resistance to flow – think of how honey flows slower than water. Selecting the correct viscosity grade (usually denoted by ISO numbers like 32, 46, or 68) is crucial. Using an oil with a viscosity that’s too low won’t provide adequate lubrication, leading to excessive wear. Conversely, oil that’s too thick can result in increased friction, reduced efficiency, and potential damage.

Temperature plays a significant role in viscosity. As temperatures rise, oil tends to thin out. Therefore, you’ll need a higher viscosity grade for hotter operating environments to maintain proper lubrication. Your compressor’s manual will specify the ideal viscosity range for your model based on its operating temperature range.

Additives

Modern compressor oils often include additives to enhance their performance and protective qualities. These additives are designed to address specific challenges faced within a compressor system. 

For example, anti-wear agents create a microscopic protective film on metal surfaces, reducing friction and minimising wear over time. Antioxidants, as their name suggests, prevent oil oxidation, a process that can lead to sludge build-up and shorten the oil’s usable life, particularly in high-temperature applications. Rust and corrosion inhibitors are also common, safeguarding metal components against moisture damage.

Another crucial function of additives is controlling foam. Even tiny air bubbles can create a layer of foam on the oil’s surface, exposing it to oxygen and accelerating oxidation. Extensive foaming can even alter the oil’s composition and reduce its lifespan, leading to pressure loss, increased energy consumption, and potential damage. 

Understanding the role of these additives can help you make a more informed decision when selecting an oil, but always prioritise the recommendations of your compressor manufacturer.

Environmental Considerations

In today’s environmentally conscious world, it’s increasingly important to consider the ecological impact of the products we use. If your compressor operates in an environmentally sensitive area or if your business prioritises sustainability, using biodegradable oils is a responsible choice. These oils are designed to break down naturally in the environment, minimising their potential for pollution.

Specific Lubricants for Air Compressor Brands: Why the Right Oil Matters

Using the correct oil recommended by your compressor manufacturer is crucial for ensuring optimal performance and longevity. Brand-specific lubricants are formulated to meet the precise needs of each compressor model, providing superior protection and reducing the risk of damage.

Why Manufacturer-Recommended Oil is Essential

Tailored Formulations
Brand-specific oils are engineered to withstand the pressures and temperatures of your compressor, ensuring smooth operation and minimising wear on critical components. Generic oils may lack the necessary additives to protect against friction, oxidation, and foaming, which can shorten your compressor’s lifespan.

Compatibility and Efficiency
Using the wrong oil can result in issues such as clogged oil filters, damaged seals, and increased downtime. Brand-specific oils ensure compressor efficiency by providing the correct viscosity and thermal stability, keeping your equipment running smoothly and efficiently.

Warranty and Long-Term Protection
Most manufacturers require specific oils to maintain warranty coverage. Although brand-specific oils may seem more expensive initially, they reduce the need for frequent oil changes and help prevent costly repairs, making them a smart investment for long-term compressor maintenance.

Using the right air compressor oil ensures that your machine operates smoothly, avoids damage, and remains within warranty guidelines—ultimately saving you money in the long run. Always follow your compressor manufacturer’s recommendations for the best results.

How Often Should Air Compressor Oil Be Changed?

Air compressors vary on the average amount of time needed between oil draining and replacement. As a rule, air compressors need annual oil changes, at a minimum. However, this is rarely the recommended timeframe for top performance.

Checking your make and model’s manufacturer recommendations is best. Factors such as dustier environments or abnormal humidity levels, as well as how the equipment is used, and the operating conditions, may alter the recommendation.

However, if you cannot find this information, then use what’s provided below as a general guide:

• Rotary screw air compressors – Most rotary screw-type compressors need oil replaced every 7,000+ usage hours. When this usage is spread over longer than 12 months, then whatever is the shorter period.
• Reciprocating air compressors – With reciprocating-type compressors, every quarter is typically the recommended interval.

Risks Associated with Using the Wrong Oil

Air compressors may operate for shorter durations without breakdowns when using an inferior lubricant. Compressor oil is not the same as motor oil or other machine lubricants that you may be familiar with. Equally, it’s not a marketing ploy to sell more oil products, either.

Bad oil can create deposits across movable parts, over the oil circuit, and elsewhere that interfere with functionality. Seals won’t function perfectly, added oxygen where it’s not needed is detrimental, and increases potential internal corrosion too. The overall lifespan of the air compressor suffers accordingly.

Critical components such as essential pumps, and even bearings lacking adequate and appropriate lubrication change pressure levels, increase unwanted friction and lead to wasted energy. Breakdowns are likelier, requiring a servicing stoppage and leading to lost productivity. Furthermore, failure rates – just like with other machinery lacking essential lubricants – increase significantly.

Due to this, air compressor operators should pay particular attention to the oils used.

Contact Us

If you need help choosing which oil is right for your Air Compressor, please contact Anglian Compressors today. 

FAQ

How do I select the right oil type for my air compressor?

Selecting the correct oil type for your air compressor depends on several factors, including the compressor model, operating conditions, and manufacturer recommendations. Always consult your compressor manufacturer’s guidelines, as using the correct oil ensures optimal performance and extends the compressor’s lifespan. For most compressors, synthetic or standard compressor oil is recommended, though some specific applications may require specialised lubricants, such as Atlas Copco oil.

Can I use motor oil or hydraulic oil in my air compressor?

No, using motor oil or hydraulic oil in air compressors is not recommended. Air compressor oil is specially formulated to withstand the high temperatures and pressures inside the compressor. Motor oil or hydraulic oil lacks the necessary additives and properties to protect the compressor, which can lead to damage, reduced efficiency, or premature wear. Always use the oil type specified by your compressor manufacturer for the best results.

How often should compressor oil be changed?

The frequency of oil changes depends on your air compressor model and its usage. Most compressors require oil changes after a specific number of operating hours, typically every 7,000+ hours for rotary screw compressors or quarterly for reciprocating models. Regular oil changes are essential for maintaining compressor performance and preventing wear. It’s also a good idea to perform regular oil analysis to monitor the oil’s condition and ensure optimal performance.