Many of our clients come to our engineers for advice on which hydraulic oil they should use in both our own bespoke mobile hydraulic systems and sometimes even hydraulic systems that we haven’t designed. However, there is not just one simple answer for this. There are of course many different types of hydraulic machines that are located in different climates etc. However, there are three basic elements that need to be considered when making your selection. Grade Whether you need a mono-grade or a multi-grade can be determined by the climate and temperature conditions. If your machine operates in the same temperature every day of the year, then you could most likely get away with using a mono-grade. This will actually be a less expensive option too. If you have freezing conditions during winter and high temperatures in the summer, then multi-grade is your answer. Detergent Oils with added detergent are able to help keep components deposit free. They are able to create an emulsion from added water, and also have some ability to handle sludge or varnish. However, these contaminants will still need to be filtered out in order to remove them. When a detergent oil is in use, it’s important to keep a close eye on how much water there is in the oil. After all, its water that can age oil, reduce its lubricity and even how well it will filter in addition to creating more cavitation and corrosion. It can also be converted into steam. Overall, it’s best to keep any water below the 100ppm level. Anti-wear If your hydraulic system is high-performance and high-pressure then you may want to look at adding an anti-wear element to your oil. This makes it possible for lubrication to be maintained. However, the downside is that there can be some negative effects. Take the additive known as ZDDP (Zine dialkyl dithiophosphate) for example. This can have undesirable effects as it begins to break down as soon as it comes across water and then can go onto corrode a variety of yellow metals. Overall, making the right selection is very important for your machine. If you don’t get it right, it’s going to cost you and your machine dearly. Therefore, it’s worth investing the time and energy to get it right.