Can You Lay An Air Compressor On Its Side?

In this article I’ll answer a question a lot of people have asked me over the years – is it ok to lay an air compressor on it’s side? *Spoiler Alert* – It’s not really! But below I’ll explain why. Firstly though, you should understand a little more about how they work, and the crucial point involving air compressor oil.

What Is An Air Compressor?

An air compressor is intended for use at various levels of industry. Indeed, this equipment is required in the majority of garages, factories, and workshops across the world. Many individuals have air compressors at home to assist them with various projects/tasks.

The air compressor is a vital companion to many tools and equipment due to its capacity to create compressed air (an energy source).

The device, as the name says, creates compressed air and stores it in a tank. The compressed air is then released to power a pneumatic tool.

For much more detail on this, please see my guide What Is An Air Compressor?

How An Air Compressor Works

The fundamental operation of an air compressor is to compress air as it enters the device and then release it at high speed and pressure on the other side. A typical piston compressor consists of a storage tank, an electric motor, intake and outlet valves, a pump, and an air discharge.

The procedure is broken into various steps:

  1. The first step is the air intake stage. The apparatus must first pull air in order to generate compressed air. The intake valve allows air to enter the air compressor.
  2. The compression of air in a compression chamber follows in the second step, sometimes known as the compression stage. The conversion of kinetic energy in the air to potential energy or pressured air is involved. How this is accomplished varies depending on the compressor type.
  3. The next level is known as integrated storage. Following the compression process, the air may be routed to a storage tank or an air tank. Air is kept in restricted duty units so that it may be used during downtime. This kind of storage is seen in shop compressors. Some compressors store air and utilise it when the capacity is low. They have controls that allow them to function in this manner, thus the term “modulating compressors.”
  4. Integrated cooling comes after integrated storage. The air gets heated as a result of the compression process. While chilling the air before it exits the air compressor is not required, certain diesel units and the majority of three-phase electric machines have the capacity to do so. Typically, an after-cooler works in tandem with a water separator to remove moisture created during cooling.
  5. Discharge is the last step of an air compressor’s operation. As the air travels to the discharge point, it may go straight to the place of use or must first pass through a series of filters and dryers. It then reaches the air tool it is being used to power.

Oil-Lubricated Air Compressors vs. Oil-Free Air Compressors

When shopping for a compressor, you must pick between oil-lubricated air compressors and oil-free models. Although there is no functional difference between the two, the operation and design differs between the two types of air compressors.

For industrial applications, you should use lubricated air compressors to ensure their durability. Because the performance of oil-free air compressors is restricted, they are largely intended for home usage.

There is no oil on the cylinder walls of an oil-free air compressor. Instead, special materials are used to self-lubricate these air compressors. The movement of the piston inside the cylinder, for example, is dependent on sealed bearings.

As you’d expect from the name, oiled air compressors use oil to lubricate the working components. This difference between these two types of air compressors becomes very important when discussing whether the compressor can be stored or used on its side or when lying down.

I wrote a long article on this subject you might want to read – Oiled Vs Oil-Free Air Compressors.

Can You Lay Down an Oiled Air Compressor?

If you’re talking about an already used oiled air compressor, then you should never lay it down on its side, as this will allow oil to flow where it should not go, and contaminate the compressor components with oil and dirt. When the compressor is working, the oil in the sump splashes up from beneath onto the crank and piston, lubricating the components as the compressor runs.

After running an oiled compressor, it may have picked up some fine dirt particles which have managed to get past the air intake filter. Because these air compressors lack an oil filter, any debris or filth in the oil falls to the bottom of the sump when the compressor shuts off. When the compressor is upright, the dirt is deep enough down in the sump that it should not splash up on the compressor components while it is operating, but may be drained away when the oil is changed.

However, as with any internal combustion engine, you would not want to turn it upside down and allow dirty oil to flow into areas of the engine where it’s not supposed to go, such as the air chamber or piston bearing.

But this is not a problem with a new unit because new compressors are sent shipped without oil, therefore it makes no difference which way up they are – so feel free to put a brand new, unused air compressor on its side. However, once you have received your new compressor and added oil to it, it’s best to never lay it on its side again.

If you really have to lay an oiled compressor on its side

If you really, absolutely have to lay an oil-lubricated compressor down on its side, or have to tip it (perhaps you have to move it somewhere), then you should without doubt drain the oil out beforehand (as well as emptying the compressor tank of course!). But even then, there’s still a chance that a small amount of oil will remain inside and so just be aware that it is still a risk and your compressor may be damaged as a result.

You must then make sure you then stand it upright as quickly as possible afterwards and leave it for 24 hours or more before use. This should allow most of any remaining oil to drain back into the sump.

Finally, you should then add new oil to the compressor.

Can you lay an Oil-Free Air Compressor on its side?

If the compressor is oil-free, it is pre-lubricated for life when it leaves the factory, so there is no need to add oil, and there is no splash lubrication of the compressor pump while the compressor is running.

However, this does not guarantee they are completely safe to lie on their side. When using an oil-free compressor on its side, any built-up condensate in the air tank can combine with dirt and splash about, generating a sludge that might interfere with the tank’s valves.

If this matter were to reach and block the check valve, it may cause back pressure to build up, putting strain on the pump motor. This may cause the motor to overheat and shut down or completely burn out.

If the compressor is left on its side for an extended amount of time and the sludge on the check valve dries, it can cause the valve to stick shut.

Furthermore, the sludge may also obstruct the compressor drain valve, preventing you from draining the tank.

So you may lay an oil-free compressor down on its side only for short periods, and as long as there is no water in the tank and the compressor is securely fastened.

Can you lay an air compressor on its side for transport?

By default, an air compressor is designed to be transported on its side. This allows for easy and efficient movement, as well as prevents damage to the compressor. However, there are a few considerations that should be made before transporting an air compressor in this manner.

The first concerns whether or not it is new or whether its a second-hand air compressor. As mentioned above, only a brand new, unused air compressor should ever be put on its side, even for transport. A second-hand air compressor should never be transported on its side.

The second consideration is whether or not the compressor has been tampered with in any way. If it has been, moving it in this manner could potentially cause damage.

The second consideration is the type of road that will be used for transport. If the road is very rough or has a lot of potholes, moving the compressor in this manner could cause damage. In addition, if the road is wet or icy, transporting the compressor in this manner could be very dangerous.

If both of these considerations are met and the compressor can be moved on its side without causing damage or injury, then it should be fine to transport a new compressor on its side.

How do I transport a large air compressor?

If the compressor is large or heavy, special measures may need to be taken to support it while being transported. It also depends whether it is a horizontal or vertical type – as a horizontal will be much easier!

Before using any method to move a large used compressor, drain the compressor completely of oil, air and water! If it’s new, well then you won’t need to.

The easiest method is to lift it with a cherry picker. It you don’t own one, they can be rented fairly cheaply.

Otherwise, most retailers will happily put your new compressor onto your truck or trailer using a forklift, and then tie it down with multiple ratchet straps. I found a good video on youtube which shows how this should be done:



However, if not then you can move a large air compressor with just two people, but it can be dangerous so please use extreme caution. You are merely lifting a tiny portion of the weight with this method:

  • Tie it down to the front of the truck bed and tighten it as you move the compressor farther into the bed.
  • Put a moving blanket or pallet in the vehicle and position the compressor approximately 2′ from the tailgate.
  • Get a buddy to assist you, using the tailgate as a fulcrum, and then slide it in. You can see this method in reverse at the end of the video above, as they use it when unloading the compressor.

Can a horizontal air compressor be stored upright?

A horizontal compressor can take up more room than a vertical type, so it can be more tempting to turn it onto its side to save room. However, for the same reasons detailed above, this is again not a good idea as the oil and dirt can then trickle into the places it shouldn’t go. So follow the same guidelines above – empty the oil out, minimise the time spent on its side, then return to its normal position and leave for 24 hours before adding new oil.

What happens if an air compressor is not drained?

If you do not drain your compressor, then moisture can remain in the tank which then causes it to rust, which weakens the tank’s structure, which can then lead to the air compressor tank exploding – this can be lethal. So you must drain the air compressor on a daily basis, or after every time you use it.

Keep drain valves open too. After you have removed all of the water from the tank, do not reseal it. Allowing it to stay open enables air to circulate within. Even the smallest drop of water may cause rust to form, but leaving it open can help you ensure that all water has gone. When using this method, please make sure that the tank is put in an area where more water cannot enter.

Jeff Stelling

Jeff Stelling is an air compressor obsessive who has been working with compressors for over 25 years, since he was an apprentice engineer in the mid 90’s. He designed to offer technical guidance and buying advice for compressors.

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