Air Compressor Oil – How To Check, & How Much To Use

Air compressors can be the foundation of our workshop. If they break down, we’re not going to be getting much done that day. So it’s important we look after them correctly. Monitoring oil is one of the best practices when it comes to the proper maintenance of air compressors.

You need to monitor air compressor oil to ensure that the compressor is well lubricated. Making it a habit to regularly check your air compressor’s oil helps you to know when you’ll need to change it. Always having enough oil keeps the air compressor cool and sealed: extending it’s lifespan.

If your air compressor wears out or breaks down, repairing it could be very costly. Read on to find out how monitoring oil prevents damage in compressors.

The Importance of Monitoring Air Compressor Oil

When using a lubricated air compressor, it’s important to check your oil because:

1. Oil acts as a cleaning agent

Air filters are designed to catch most contaminants and particles before they get into the compressor. However, some nanoparticles, which are hard to capture, are still found in the air.

These nanoparticles can be in the form of free water from water vapor in the air. They can also be in the form of dust from air molecules being squeezed together.

Oil captures these nanoparticles and all other particles that are produced by the metal parts of the compressor. The particles can then be removed every time you change your oil. In turn, this enables the compressor to function efficiently.

2. Oil helps in the compression process

Oil helps in the compression process by sealing gaps between screw elements. The screws that join metal parts can sometimes make air compression hard because they leave gaps in the machine.

Oil is good at reaching the smallest positions, which ensures that the system is totally sealed. Consequently, the sealing by oil prevents air from escaping and keeps it compressed.

3. Oil cools the system

Since air compression is a continuous process that generates lots of heat, temperatures in the compression chamber tend to rise. Oil acts as a primary coolant, keeping the compressor cool. If heat is not rapidly removed from the chamber, bearings, seals, and gears will fail.

4. Oil prevents wear and corrosion

As we mentioned at the beginning of the article, lubrication is one of the functions of air compressor oil. Since a number of moving parts such a bearings help in compressing air, it is important to keep them lubricated.

5. Oil saves on cost

Monitoring air compressor oil will lower costs by:

  • Minimizing scheduled maintenance costs
  • Increasing compressor longevity
  • Reducing fuel consumption

Knowing how important oil is to the smooth running and longevity of a compressor, it makes sense to monitor it. You should check your lubricant for contamination, which could affect the acidity and viscosity of the liquid.

How to Check Your Air Compressor Oil

If you have not been monitoring your compressor oil, you can begin doing so using the following tips:

#1 Check oil level

Inspect your oil level 3-4 times a week to make sure that your compressor does not run low on oil. Compressors have either a dipstick or a sight glass that you can use to check the oil level.

All dipsticks are calibrated, and you should make sure that your oil level is always near the max mark. Some sight glasses are not calibrated. However, this should not worry you. The trick is to make sure that the oil level is 2/3 full on the sight glass.

#2 Check for oil leaks

An undetected oil leak will leave your oil pan empty, putting your engine at the risk of damage. Check regularly for leaks by watching for pooling of oil at the base of the compressor and engine.

Note that if you constantly have to keep refilling your oil pan, the compressor might be leaking an excessive amount of oil.

#3 Check oil quality

As oil gets used in the compressor chamber, it gets old and worn out. Old and worn-out oil could affect the efficiency of your air compressor. If your oil is thick and opaque, has grainy particles, and smells bad, then its quality has degraded. Therefore you ought to change it.

To check oil quality, use the dipstick or sight glass methods. If these methods do not give you a clear answer, use other methods such as the blotter test.

If you suspect that your oil is degrading faster than it should due to contamination, a professional will perform the IR or TAN test to confirm this.

#4 Change compressor oil

If your oil has aged, change it. Remember that oils vary depending on their viscosity. Check your manufacturer’s recommendations before purchasing new oil. Usually, it is recommended that you change oil after every 1000-2000 hours of runtime.

Frequently Asked Questions

Can I use motor oil in my air compressor?

Whether to use motor oil in an air compressor is a question that most people ask. That said, using motor oil is not a wise idea for this reason.

Motor oil contains detergents and other additives, which, when heated during compression, will produce foam. This foam inhibits the lubrication process.

Besides, motor oil might cause a build-up in the compressor’s pump. A build-up will put a strain on the pump, reducing its effectiveness and causing it to wear faster.

What kind of oil should I use in my air compressor?

To ensure that your air compressor runs smoothly:

  • Use the oil that your manufacturer recommends as the system is designed to use that oil.
  • In case you do not know the oil that is recommended for your compressor and cannot find the user manual, use 30W ISO 100 OR 20W ISO 68. These are the most commonly used oils.
  • Avoid oil that is organic or has detergents.

How much oil does my air compressor need?

Since oil is very important to an air compressor, it can be quite tempting to fill it up to the top for “extra” protection. However, excessive oil is dangerous as it can cause internal damage to the compressor when it spills over. Additionally, the oil might also damage other parts and accessories that the air compressor is attached to.


One of the best practices that will prevent your air compressor from getting damaged is changing lubricants according to the manufacturer’s recommendations. Overstretching maintenance intervals, especially in hot, humid weather, will lead to compressor failure. Make sure that you monitor your air compressor oil regularly using the tips discussed in this article.

I hope this article’s helped you better understand monitoring your air compressor’s oil. If it has, please consider supporting us by checking out some related articles.

Thanks for reading, and have a great day!