An industrial air compressor is a hard-working machine, and like so many machines working in industry, they require oil for lubrication and to operate smoothly. But why do you need to add oil to your air compressor? Is it the same as the oil that you use with your pneumatic tools? Is there a particular type you should use? How often does it need to be changed during its life span? Is there a particular viscosity that is better than others? Is there a specific standard that needs to be followed? Heres an in-depth look at using oil in air compressors, including what types, how often and much more.
An air compressors oil is designed specifically for the demands that an air compressor faces daily. Unlike motor oil, which often has a comparable price point and may be easier to find, air compressor oil does not contain detergents, and often has much lower amounts of carbon and sulfur, which are commonly found in motor oil. Motor oils are designed to operate in lower temperatures and higher volumes than air compressor oil, so if you try to substitute motor oil in your air compressor, it can fail, because motor oil breaks down at lower temperatures than air compressors operate at and can oxidize at much lower temperatures. For this reason, its very important to use the correct type of oil for your air compressor, which will withstand the high heat and has gone through evaporation, desalting and solvent extraction processes to make it work well in those conditions.
Air compressors tend to build up heat, especially in the pump assembly. Oil helps not only dissipate some of that heat, but also keeps the interior parts lubricated, so they dont bind up or stick when they reach those higher temperatures. It also keeps the surfaces inside your air compressor pump coated, preventing oxidation and corrosion. Regularly changing the oil in your air compressor ensures that it will last for many years to come, giving you a much longer overall life span as compared to an air compressor that does not receive regular maintenance. To protect your investment, make sure to keep up with this important maintenance step.
Unfortunately, the simplest answer is that it depends. To start, if possible, check your owners manual to see how often the oil should be changed in your air compressor. However, if you dont have your manual and cant find a copy online, there are some general guidelines that can help. If you have a reciprocating air compressor, youll want to look at changing the oil every three months if using conventional oil, or up to every six months using synthetic oil. If you have a rotary screw compressor, youll want to change the oil every 1,000 to 2,000 hours if youre using conventional oil, and every 2,000 to 4,000 hours if using synthetic oil. The time period will be impacted in both cases by how dirty and dusty the environment is, how long your compressor is running at a time, and similar factors. The easiest way to tell, especially when youre just starting the process, is to check how dirty the oil looks, or have it tested to see how well its holding up at various points in the duty cycle.
So, what if you just cant find air compressor oil? Although its best to stick with the right type of oil for your industrial air compressor, there are a couple of other options that can work well in a pinch. Hydraulic oil is designed for heavy usage, and so is a decent option to consider if you need to make substitutions. Similarly, because its often used in lower volumes than motor oil, transmission oil can be used in many situations where you dont have air compressor oil available for your compressor. If you find that youve put motor oil in your air compressor, change it ASAP.
Though its fine using either, the choice of which is best will often depend on how you use your air compressor. If you typically only use it for short periods of time, such as the short periods of cycling to refill a tank on your home air compressor or to run it less than three times weekly, using regular oil will work fine and will often save you some money over buying a synthetic oil. However, if your air compressor is running almost constantly, or if youre using it three or more times a week, youll want to switch up to a synthetic oil, which will last much longer and provide a higher degree of protection in your air compressor pump. Synthetic oils also deal better with a wider temperature range and allows your air compressor to run more quietly and smoothly in most situations.
Though its easy to fall into the idea that oil lubricates, so any oil should do, when you get deeper into engineering, youll find theres a huge difference between oil types. What makes air compressor oil stand apart is that it has several specific properties that are keyed into air compressor usage. These include heat dissipation, resistance to oxidation, better viscosity in cool temperatures, anti-foaming ability, longer life span, and demulsification. In short, it helps keep your commercial air compressor cool, resists rust, keeps flowing in the cold, doesnt create rust-inducing foam, works for longer between oil changes, and keeps any water separated from the oil to provide better protection and easier separation later.
Though these are typically limited to very small household compressors or tire inflators, oilless air compressors arent without oil, but have had a specific amount added at the factory, at which point the air compressor is sealed. However, over time, the oil in the compressor will eventually degrade and burn off, at which point the compressor will seize up. For this reason, we dont recommend oilless air compressors for any serious usage, because theyre essentially short-term disposable items.
Most modern air compressors work well at an SAE 20 or 30 weight oil, so where should you be watching for the difference? A 20SAE oil will have a better flow at lower temperatures, making it a better option for winter operations if your facility tends to cool down during the cold months, but will break down and oxidize more readily in the hot summer months. Similarly, a 30SAE oil is more resistant to breaking down, making it a better option in the summer, while its higher viscosity in the winter can make your compressor run less smoothly and efficiently. But what do you do if you live in extreme climate conditions? Though youll want to talk to a local air compressor shop or two to see what their standard is for your area, extreme cold could see you stepping down to a 10SAE while extreme heat could step you up to a 40SAE.
While you can find this information specifically in your owners manual in many situations, there are several ways in which the manufacturer makes this possible. The first is the inclusion of a dipstick, often found attached to the oil fill cap. The second is a window that shows what the oil level is in the machine. Some manufacturers have also moved to making a completely clear oil reservoir, making it easy to see from a distance. The last type that youll typically find is a porthole, through which you should see some oil if the air compressor is good to go. You should typically check the oil level when the industrial air compressor is cold, as oil expands when it heats up and may appear to be in a proper zone, but the level will drop outside of the appropriate levels after the air compressor and oil cools down following use.
By having a solid grasp of why its important to not only use the correct oil in your air compressor but also what types to use and how to maintain your air compressor. This allows you to get much more use out of your industrial air compressor for many years to come. If youre at the point where you have concerns about your commercial air compressor, need parts or service, or are considering getting into a new air compressor system, the experienced professionals at Advanced Air are ready to help. Please feel free to contact us today with any questions, for more information, or to get a quote on some of our outstanding products and services.
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