Although different models of air compressor will differ slightly, the general concept of changing oil will work. The first thing you must do is ascertain whether your air compressor uses oil as not all air compressors are oil lubricated. If you use a small DIY compressor the chances are that it won’t use oil. If your compressor is fully shrouded then it won’t as the shroud should not be taken off. You can identify whether your air compressor is oil lubricated if it has an oil pan or sump. The oil pan holds any oil that is added to the compressor until it is turned on.
Once the air compressor is switched on, oil is fed to the areas which require lubrication. Depending on how your compressor works it may or may not require installation of expensive oil pumps. However, most DIY models will not.
It is crucial that you only use compressor lubricating oil in your air compressor as it has specific additives which are required. You could damage your air compressor by not using the correct oil. Change the oil on a regular basis, as you would in your car.