An air compressor is either oil-free or requires oil to operate properly. Oil, as a lubricant, keeps the machinery operating smoothly and at a lower internal temperature. Insufficient compressor oil – or the incorrect type for an industrial air compressor – impacts operational efficiency, boosts energy demand, and reduces equipment lifespan.
It is valuable to learn about compressors and the oil they require. Better quality oil does reduce friction on moving parts. Friction and wear are key factors affecting compressor longevity. Therefore, a smart decision about compressor oil early on pays dividends later.
Below is our guide to air compressor oils.
Table of Contents
Types of Air Compressor Oils
Synthetic Oils
Synthetic compressor oils deliver improved performance compared to mineral oils. They are scientifically engineered to offer higher viscosity, reduced oxidation properties, resistance to high-temperature exposure, and better performance under pressure. In certain circumstances, these synthetic oils are suitable for food production environments when the machine is filled with fully-synthetic food grade oil.
Smoother operations through reduced friction result in lower energy costs.
Your air compressor may require synthetic oil because of high peak internal temperatures at certain air pressure levels. Alternatively, the manufacturer may recommend synthetic oils as a performance enhancer. They are also known for extending the length of time between oil changes.
Semi-Synthetic Oils
Semi-synthetic oils strike the balance between synthetic and mineral compressor oils – giving you a little of both worlds.
They have improved viscosity, lower residue deposits, and are not as expensive as synthetic compressor oils. However, you do not get away from all the negatives of mineral oils.
Semi-synthetics are a potential middle ground when aiming to strike a meaningful balance between costlier synthetics and accessible mineral oils.
Mineral Oils
Mineral oil is the earliest type of oil. It is referred to by various names for compressors, including standard compressor oil and mineral oil.
It is more affordable than synthetic or semi-synthetic compressor oil. However, there are trade-offs to consider.
The oil flows less well while achieving reliable thermal consistency, particularly at higher temperatures or humid conditions. It leaves tell-tale deposits and sludge build-up, requiring more regular maintenance shutdowns. Also, the oil must be completely replaced more frequently.
Factors Influencing Oil Choice
It is easy to overlook the importance of compressor oil selection. Nevertheless, no one size fits all.
Every air compressor model operates slightly differently. What is optimal for one model is not always the same for another. Therefore, whilst a previously owned air compressor might have accepted a mineral oil with few inconveniences the same is not automatically true for other compressor makes and models.
Sometimes internal operating temperatures vary between models, or simply due to the settings. For example, temperatures are often higher when requiring higher pressurised air. Your chosen compressor oil must be capable of maintaining its flow rate and reducing friction. Synthetic oils and semi-synthetic oil types are superior at higher internal temperatures.
Also, bear in mind that air compressor manufacturers indicate the type of oil to use. Using a different type of oil than what is recommended may, in a worst-case scenario, void the equipment’s warranty due to potential compatibility issues.
J LL Leach provides advice for compressor owners who are unsure about air compressor oil selection.
Viscosity and Additives
Two aspects of compressor oil to be aware of are viscosity and additives.
Viscosity
Oil flows over the parts to keep them well lubricated and reduce heat build-up. Viscosity refers to a resistance to the necessary flow movement.
UK viscosity ratings confirm an oil product’s level of flow resistance. Lower ratings indicate that the oil flows well in cold conditions but less well in hot ones. Conversely, higher ratings confirm that the oil is well suited to high-temperature internal operating environments.
Look out for oil ISO ratings like the following:
- ISO 32
- ISO 46
- ISO 68
Additives
Oil additives provide useful features that otherwise would not be present.
Additives found more often in synthetic oils include:
Anti-wear: these reduce friction on internal compressor parts for better longevity and less frequent maintenance needs. Clogging is also reduced.
Oxidation inhibitors: these help the oil retain the same chemical and other properties when exposed to air, water, or dust. They maintain optimal performance for longer and extend the oil’s life.
Environmental Considerations
Environmental factors are increasingly important to businesses. In some circumstances, biodegradable compressor oil is available for compatible air compressor machinery with a higher potential environmental impact.
More UK environmental regulations complicate the decision. If you are leaning in this direction, we recommend talking with one of our air compressor experts. They can guide you through the various oil choices for your air compressor, allowing you to strike a balance between an environmentally friendly solution and operational efficiency.
Changing and Disposing of Compressor Oil
Air condensate is the oily water mixture resulting from air compressor usage. With oil-based air compressors, oil and water separators clean the water and collect oil remnants separately. Oil/water separators are necessary equipment for oil-based systems.
The wastewater is then usually compliant with local environmental laws relating to waste disposal. Removing the water through the waste drain is now appropriate. The separated oil must be disposed of safely and in accordance with environmental laws. Fines of upwards of £20,000 are possible when failing to do so.
Common Problems and Solutions
Air compressors operate within a range of temperatures. When running at near capacity or at higher air pressure levels, temperatures hit their peak. Overheating is a hazard that requires monitoring to prevent it.
To moderate temperature levels, use the best oil type for your compressor and lubricate appropriately. Excessive friction caused by insufficient oil quickly leads to overheating and equipment shutdowns. Engines and other parts can become damaged when too little oil, or the wrong type, is used.
Wear and tear are potential issues with any mechanical equipment. Proper oil levels allow smoother running and lessen unwanted vibrations. Depending on the type of air compressor, internal movements may rely on friction to compress air. This makes it even more critical to ensure lubricants are at appropriate levels to avoid damaging valuable equipment.
Conclusion
Do not let compressor oil become an afterthought. Selecting a recommended oil protects your capital investment. Choosing poorly can potentially increase expenses during ownership and reduce equipment lifespan.
If you have questions about air compressor oil, contact our talented team at J LL Leach to help you choose the right one.
