Oil Contamination

What is Oil Contamination?

Oil contamination is by far the greatest cause of poor reliability in oil filled systems, but what is it? Well basically oil contamination is anything that doesn’t belong in your oil. Typically this includes hard particles, moisture, wear elements etc. But it can also include oil ageing products, depleted additives, incorrect oil, cleaning solvents, airborne elements, air entrainment. There are so many things that can lead to poor oil performance and our job is to help you identify them by using the best oil analysis and taking the best necessary action.

Where do the Contaminants Come From?

Considering the oil contaminants mentioned above (not an exhaustive list) here are a few ideas where they may come from. Again, not

Hard Particles: Poor machine or components installation practices, ingress through seals, ingress through Breather Port, poor oil storage, maintenance activities. Did you know hard particles not only lead to component wear, but can act as catalysts for oil ageing…………?

Moisture:: Ingress through Breather Port leading to condensation, cooler leaks, ingress through seals etc, poor oil storage by-product of oil ageing. Did you know the presence of moisture not only reduces lubricity, but can increase the rate of oil ageing…………?

Wear Elements: Corrosion, erosion and abrasion of internal components. Did you know that not all elements are detected in oil analysis? They need to be the right size………?

Oil Ageing Products: Caused by oil oxidation. Did you know that hard particles, oil temperature, moisture all increase the rate of oil ageing. And the oil degradation products lead to those straw coloured deposits on your pumps, valves, tank walls etc……………?

Depleted Additives: Mostly anti-oxidants and caused as a natural consequence of oil ageing. Did you know that depleted additives behave like oil ageing products and lead to deposits in your system…….?

Incorrect Oil: Poor top-up practices. Did you know that cross oil contamination can lead to poor air release…………………….?

Solvents: Using incorrect methods to clean tank/components etc. Did you know some solvents can affect the air release properties of the oil, which in-turn reduces the oil life……..?

Air Entrainment: Poor air release properties of the oil (sometimes caused by cross oil contamination), running oil level too low in the tank. Did you know air entrainment can lead to ‘micro-dieseling’ which can rais localised temperatures to 1,000°C…………….? It can drastically accelerate the ageing

A Word on Oil Ageing Products

The majority of contaminants in used oil are oil oxidation products and depleted additives, which are all there because the oil is ageing. These are mostly sub-micron, so they are not recognised by conventional oil analysis. Furthermore, they are not removed by conventional filtration. If left in your machine, oil oxidation ageing products will create layers (varnish) on internal surfaces, including pipework, valves, bearings, pumps etc. Over time varnish reduces clearances and also traps hard particles (the sandpaper effect) resulting in high friction, wear and ultimately plant failure. So managing oil ageing products can have significant reliability benefits. Conventional filtration is not capable of removing oil ageing products as they are mostly too small in nature. Furthermore, if mechanical filtration is now well known for causing ‘filter sparks’ which can damage the oil by cracking oil molecules and accelerating oil oxidation.