Regular oil changes should be performed on most air compressors, especially those that are heavily used in a shop environment. Failing to do so or using the wrong type of oil can have bad consequences for the operation and lifespan of your compressor. That is why you should understand the importance played by air compressor oil as well as how to properly perform an oil change. Below is more information on lubricants and a step-by-step guide to changing the oil inside your shop's compressor:
Compressor oil - What it does and why the right oil matters
Though you may not have previously considered its importance, the oil inside your air compressor performs several critical roles beyond lubrication of moving parts. Here are a couple of the most important:
Cooling of components
Sealing micro-sized gaps between components to prevent air leakage
The compression of air generates a tremendous amount of heat, and since air compressors used in a shop environment are typically not water-cooled, that leaves air cooling and oil cooling as the only alternatives for heat dissipation. Compressor oil absorbs heat from the device and prevents the unit from being damaged as a result of heat buildup. In fact, it is not unusual for air compressors to greatly exceed the boiling point of water (212 degrees Fahrenheit). Such a heat load requires special oils that can handle these high temperatures, so that is why air compressor oil must be used. A failure to use the proper oil can lead to thermal breakdown and cause the oil to leave a varnish-like film on the internal parts of the compressor. In the same way, continuing to use oil past its useful life can result in the same problems, which is why regular changes are important to the well-being of the compressor.
How to perform an air compressor oil change
As you have seen, using the right oil for your compressor is critical, and making the correct selection is the first step to take when preparing for an oil change. Your compressor's manufacturer will provide guidance regarding the correct oil specifications, so be sure to adhere to these when making your purchase. Once you have the oil in hand, you are ready to perform the change:
1. Heat the oil inside the compressor - Start the compressor and operate it for several minutes to heat the interior components and the oil by extension. Hot oil will flow much more easily and allow you to drain the compressor more completely.
2. Drain the oil from the compressor - Once the compressor has run for several minutes, turn it off and disconnect its power source to prevent an accidental start-up. Next, position an oil drain pan beneath the bottom of the compressor to catch the old oil. If your compressor's drain plug opening allows you to attach a hose to route the oil into a container, then utilize this capability if it is helpful.
When you are ready to drain the oil, remove the oil filler cap to remove the vacuum inside the oil sump; this will enable the oil to drain more freely. Next, carefully remove the drain plug and allow the oil to flow into the pan or container. Be sure to avoid getting the hot oil on your hands to prevent burns. Monitor the draining oil and replace the drain plug as soon as the oil flow slows to a drip once every few seconds. If your drain plug uses a washer, replace it with a new washer to help prevent leaks.
3. Add new oil to the filler tube - After all the old oil has been removed and the drain plug replaced, insert a funnel into the oil filler tube. Begin pouring clean oil into the filler tube slowly and monitor the sight glass, if the compressor is so equipped, to see when the oil reaches the proper level. If there is no sight glass present, use the compressor's dipstick to gauge how much oil should be added and when to stop pouring. When you are finished adding oil, replace the filler cap and wipe away excess oil with a shop cloth or rag.
4. Restart and monitor the compressor - Once the new oil has been added, restart the compressor and watch its operation for a few minutes to ensure the oil is being distributed properly inside the compressor. Stop the compressor after a few minutes of operation and check the oil level to ensure you do not need to add any additional oil; if the level is low, pour more oil into the filler cap as instructed in step 3.
Contact a company that services air compressors to learn more.