Do oil-free portable air compressors need maintenance?

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There is this notion that an oil free air compressor is also maintenance-free, which is false. Any tool or equipment deserves TLC (tender love and care) if you want it to remain in good working condition for a long time.

Even the so-called maintenance-free batteries for cars require cleaning of the terminal posts to remove oxidation and improve electrical connection.

The same applies to air compressors. Whether oiled or oilless, air compressors require regular maintenance. It is only that the amount of work needed to service an oil-free compressor is a fraction of the effort you put into keeping an oil-lubricated air compressor in perfect working condition.

How to maintain an oil-free air compressor. (6 Ways)

Maintaining an oil-free air compressor is not hard at all. These are the few measures you can take to keep them in good working condition for a longer time.

how to maintain a portable oil free air compressor

1. Do not exceed the maximum tank pressure

One of the precautions you must take with any air compressor is to avoid exceeding the maximum tank pressure. This is the PSI rating often expressed along with the tank capacity. For instance, you will find 1-gallon tank with 120 PSI, or 6 gallon tank with 150 PSI Max.

Every air compressor has a tank gauge to show the pressure of air in the tank so that you dont exceed the maximum rating. They also have a pressure relief valve at the top to help you bleed off excess air in case you exceed the pressure.

Exceeding the maximum PSI rating of the tank could cause the tank to explode and cause a serious accident. Even if the tank does not burst violently, too much pressure over time could cause the pressure-release nozzles to start leaking.

2. Release the compressed air before storing the compressor

Always empty the air receiver tank before storing the air compressor. This helps to prevent the build-up of moisture as compressed air condenses when the ambient temperature drops.

To release the air in the tank, simply pull out the air relief valve, typically at the top of the tank. Compressed air will escape into the atmosphere.

3. Drain the tank regularly

When compressed air enters the receiver tank, it cools down and the water vapor in the air stream condenses. This results in water collecting at the base of the tank.

If the water is not drained regularly, it can cause corrosion inside the tank and degrade its integrity. Most air compressor tanks are prone to corrosion and rust because they are steel.

To drain water from the air compressor tank, simply open the drain valve at the base of the tank. Water and dense humid air will flow out and this will prevent the tank from corroding and failing prematurely.

4. Check for air leaks

A leaking air compressor may fail to build enough pressure in the tank to run your air tools. It may also cause the motor to overrun, overheat, and fail prematurely. If it is a battery powered compressor, the battery may fail to give you a decent run time.

An easy way to check for leaks is to listen for any hissing sound at the compressor fittings. You can even soapy foam water on suspected parts to see if air bubbles will form.

5. Replace the brushes of a brush motor

Although most portable oil-free air compressors use brushless motors to run the pump, some compressors use brush motors. Brush motors are less efficient but cheaper than brushless motors. They also require the carbon brushes to be changed routinely when they wear down.

If your oil-free air compressor uses a brushed motor, make sure you replace the brushes as per the repair manual. It might not be easy to replace the brushes, by yourself, so you might want to seek the help of a skilled technician to avoid damaging the compressor.

Some of the signs of bad motor brushes include a burning smell, reduced motor performance, and sparking.

Brush motors produce a burning smell that becomes more apparent as the carbon brushes wear down.

As far as motor performance is concerned, bad brushes will cause the motor to fail to pump enough pressure into the tank. This might be a problem with either the pump or the motor. But because the motor runs the pump, it is the first culprit. If you replace the brushes and nothing changes, then you know the problem is in the compression pump.

Lastly, you can tell that the brushes of your compressor motor are worn out if they produce a lot of sparks. You will be able to see the sparks in the dark. A motor will good brushes produces small sparks that get pronounced as the brushes wear down. The increased sparking of the brushes may also cause the motor to overheat.

6. Keep the air compressor clean

Always keep your oil-free air compressor clean. Dust and debris can clog the air intake and cause the performance of the compressor to deteriorate.


To sum it up, oil-free air compressors require maintenance. Don’t get fooled into thinking that oil-free means maintenance-free. Just don’t exceed maximum tank pressure, expel the air from the tank when the compressor is not in use, check for air leaks, drain water from the tank regularly, and replace the brushes on a brushed motor. Doing so will extend the life of your oil-free air compressor.


Hey there! I am an field electrical engineer by day, a blogger by night, and DIYer on weekends. Throughout my career, I have used many tools and learned that getting the right tool for the job is the first step to getting the job done right. This is why I write about tools and tests/reviews them on this blog.

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