Air compressor oil is the top choice for reducing friction and improving longevity, but sometimes you may find yourself in search of a substitute for air compressor oil.
Whether the oil in your air compressor evaporated, dried up, or leaked out, you’ll need to replenish it quickly to avoid any mechanical damage. If you don’t have access to a proper mineral-based air compressor oil, you may have to find a substitute.
The top three air compressor oil substitutes consist of automatic transmission fluid (ATF), hydraulic oil, and non-detergent motor oil.
While standard air compressor oil is always a top choice for fluid replenishment, there may be circumstances where this option is not available. You may improvise, and these three air compressor oil substitutes are the closest you can get to actual air compressor oil.
Whether you need to top off the oil in your air compressor or completely replace it, you’ll want to find an alternative that won’t hurt your air compressor. Finding an alternative that closely resembles air compressor oil is the best you can do when you’re in a bind. Here are the top choices that most closely resemble air compressor oil.
Air Compressor Oil Substitutes
1. Automatic Transmission Fluid
As a type of hydraulic fluid, automatic transmission fluid is a surprising alternative for air compressor oil. Yet, it is a good option if you’re in a pinch. Sharing many of the same properties and attributes as air compressor oil and the other substitutes listed above, automatic transmission fluid works well.
It’s convenience is also a benefit, since most homeowners will typically have a bit of extra transmission fluid in their garage or outbuilding.
When considering automatic transmission fluid as an oil alternative in your air compressor, you’ll want to note that many types of ATF also have additives. Commonly used to prevent oxidation and corrosion, these additives can actually assist in extending the life of your air compressor.
However, you should also be aware of the downfalls of using automatic transmission fluid as an air compressor oil substitute.
ATFs oftentimes contain detergent, which can lead to the accumulation of grit and carbon buildup inside your air compressor.
Over time, this can lead to premature wear of your air compressor, which isn’t desirable. Therefore, automatic transmission fluid would work in a bind, but you certainly don’t want to use this alternative as a long-term fix.
The thickness and smoothness of an air compressor oil substitute should be considered, as well. The oil within an air compressor is used to reduce friction, so alternatives with different viscosities can affect the performance of an air compressor.
The viscosity of ATF is typically much lower than that of air compressor oil, but it will vary based on the surrounding temperature.
This can work to your benefit in colder temperatures, as the mixture becomes thinner, and aides in starting your air compressor. However, the thinner viscosity of ATF may cause your air compressor to be improperly lubricated, which can affect performance and actually do harm to your machine.
2. Hydraulic Oil
Falling under the same category as hydraulic fluid, hydraulic oil is also an acceptable substitute for air compressor oil if you find yourself in a bind. Typically, hydraulic oil is used to transfer power within machinery, such as hydraulic lifts and power steering systems.
However, it also functions similarly to air compressor oil in that it lubricates, cools, and prevents oxidation and corrosion. Just like with ATF and non-detergent motor oil, there are a few things you should consider before using hydraulic oil in your air compressor.
Different Types of Hydraulic Oil
While you may have a quart of hydraulic oil laying around at home, you’ll want to know what type it is and how well it will work as an air compressor oil substitute.
Universal hydraulic oil is the most basic, but best alternative for air compressor oil.
If you don’t have any universal hydraulic oil on hand, you can easily find it at an auto parts store or a hardware store. There are some types of hydraulic oil that contain detergents, so you’ll want to avoid those options to prevent harming your air compressor.
Most types of hydraulic oil won’t contain detergents, but there are a few that do. So, you’ll want to read the labels carefully before using hydraulic oil as a replacement for air compressor oil.
Be sure to avoid any type of hydraulic oil that is made for a specific purpose or system, as well. This may include power steering fluid or brake fluid. These types of hydraulic oil are made specifically for those systems and can actually damage your air compressor.
Some types of hydraulic oil may be labeled as “AW,” which stands for Anti-Wear. This doesn’t necessarily mean it would be bad for your air compressor, as it likely contains additives to prevent corrosion and oxidation. This is just fine for use as an alternative for air compressor oil.
Although hydraulic oil is not typically measured using the same scale as air compressor oil, their viscosity is pretty similar. The higher the ISO or SAE rating the thicker the oil is, and hydraulic oil is measured as an ISO 32 or ISO 46.
Many air compressors take an SAE 30 oil, in which case you would want to use ISO 32 oil as a substitute. This is especially true if you’re working in cooler conditions, but in milder weather either grade of hydraulic oil will serve the purpose of replacing air compressor oil.
Just be sure to stick closely to the viscosity of your air compressor’s oil when trying to find a replacement, and you should be just fine.
3. Non-Detergent Motor Oil
By this point in time, we’ve highlighted the dangers of using detergents in any type of air compressor replacement oil. So, it makes sense that you’d want to steer clear of motor oil with detergents in them as a replacement for air compressor oil, as well.
Any type of oil you use as a replacement in an air compressor should be labeled as “ND,” or “Non-Detergent” to ensure proper function.
Dangers of Detergents in Motor Oil
Many types of oil contain detergents in an effort to clean the internal parts within combustion engines, but they don’t serve the same purpose in air compressors.
In fact, detergents can prevent heavy grit from descending to the bottom of an oil pump, leaving them suspended in the oil. As a result, a buildup of grime can form on the cylinder walls and piston that can actually damage your air compressor’s motor.
Many air compressors use SAE 20 or SAE 30 oil, so finding an alternative that resembles that viscosity is important in the maintenance of your system. With SAE 20 being thinner it is more ideal in colder environments for start-up, while SAE 30 can be used in warmer temperatures.
It is always best to choose an alternative that is close to your air compressor oil’s original “weight,” or viscosity.
As such, your air compressor’s manual will tell you the best oil viscosity to use. Some even give motor oil rating alternatives, which is quite convenient. Avoid using multi-viscosity motor oil, like 10W20, because it can cause a foaming reaction when used in an air compressor.
What is the Best Air Compressor Oil Substitute?
There are three main substitutes that are acceptable for use in air compressors, but not all of them are created equal. Some are better suited for use in cold climates, while others take the place of air compressor oil just fine in mild temperatures.
The most versatile and best air compressor oil substitute is going to be synthetic motor oil. This is partly due to its viscosity, lack of detergents, and acceptable additives. Furthermore, a 20W or 30 W motor oil is going to be your best option to get the viscosity you’re looking for in an air compressor oil substitute.
Viscosity relativity is our main reason for choosing this oil alternative over the rest. Take a look at how viscosities compare between regular air compressor oil and alternatives, like ATF, hydraulic oil, and motor oil.
Air Compressor Oil Substitute Viscosities
|Type of Oil||Viscosity||Notes|
|Air Compressor Oil||SAE 20 or 30||N/A|
|Automatic Transmission Fluid||12-30 (Depending on Temperature)||No detergents.|
|Hydraulic Oil||ISO 35-ISO 110||Lower is better.|
|Motor Oil||20 W or 30 W||No mixed SAE.|
At any rate, air compressor oil is your top choice of lubrication for any air compressor. However, when you are in a pinch and need another option, the top three alternatives are recommended based on their viscosity relative to air compressor oil.
Please note, that these are not long-term fixes. We only recommend these alternatives for short-term use to help preserve your air compressor and avoid long-term damage.
Whether you need to top off the oil in your air compressor or completely replace it for a short period of time, you have a few options to consider as acceptable alternatives. The types of oil that most closely resemble air compressor oil consist of automatic transmission fluid, hydraulic oil, and motor oil.
However, there are several things to consider before selecting a proper alternative. These include relative viscosity, availability, and additives or detergents. We’ve provided the basis for selecting the ideal air compressor oil alternative, but the end choice is up to each individual.