Why you should be using a good quality hydraulic oil


A simple Google search of "hydraulic oil" will return an array of oils and fluids from all different manufacturers. So, which one do you choose? Your initial thoughts may be along the lines of "I just need something to put in that will do the job".

This may be the case but never has the phrase 'buy cheap, buy twice' been so true, in fact maybe the right phrase is 'buy cheap, replace twice as often and replace your machine parts twice as quick'. Basic hydraulic fluid will of course do the job, for a limited amount of time. But what does a good quality hydraulic oil do? 


Why good quality hydraulic oil images - Castrol Hyspin AWS


There are many good quality hydraulic oils available on the market, for this article the properties are based on that of Castrol Hyspin AWS hydraulic oil. This is a high quality hydraulic fluid that is specifically designed to extend the life of machinery. The Hyspin range will help to:

  • Extend the life of seals within the hydraulic mechanism to stop them from drying out and splitting.

  • Prevent corrosion and oxidation within the hydraulic mechanism, therefore preventing internal damage.

  • Prevent wear of the machinery parts by coating the parts so that they do not rub against each other and cause friction whilst it is in operation.

  • Extend pump life and in turn improve reliability.


How high quality oils prevent corrosion and oxidation

When a hydraulic system is working ideally it will operate at a consistent temperature of around 130ºF, this temperature means that the system receives vented air that is dry and clean. The problem is this isn't always possible, if your system or machinery is outside for example then controlling temperature is difficult. When the temperature changes rapidly the system starts to create moisture, as this happens water enters the system and can contaminate the oil. If the water mixes with the oil it will be pumped around the system and will cause corrosion and oxidation inside the system.

Top Tip
Also known as rust is a chemical reaction between water and ferrous metasl.

Corrosion is a chemical reaction between chemicals (usually acids) and metals.


In order to deal with this problem good quality hydraulic fluids contain rust preventatives that will deposit a protective film on metal surfaces. The film is virtually impervious to water and once the oil is circulated around the machine and the film established within the system it will prevent rust.

How good oils extend service life

The temperature of the system can also have an impact on the life of an oil. As mentioned above the ideal operating temperature is around 130°F. Once the temperature reaches 165°F the oil can begin to break down, this will then start develop a build up of sludge. Mix this with dirty, humid air and the system is going to start struggling and choking, meaning that the system will stop performing at its best.

A way that oil manufacturers can slow down the breakdown is by using a good base oil, this can either be a good quality mineral oil like that in Castrol Hyspin AWS or an even more refined mineral oil like that in Hyspin AWH-M. By preventing the oil from breaking down this helps to reduce wear on the system therefore extending service life of the machine, this also means that the oil does not need replacing quite as often so the time between servicing intervals are extended.


Hydraulic oils come in many different forms but purchasing a good quality oil can help to save you time and money by extending the life of your system and reducing downtime of machines due to wear or servicing and maintenance intervals.

View our hydraulic oil range

  • Dec 15, 2016
  • Univar Tech Team

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