Below is an overview of the different tests performed on each oil sample in our S.O.S laboratory. It is important to note that each test type is not used in isolation. All of the results are used in conjunction with each other to ensure accurate interpretations and recommendations.

Our experienced S.O.S Interpreters understand how the different test results relate to each other. Importantly, they are also able to look at the trend of previous sample results in order to make a valued judgement on the condition of the fluid compartment. A deviation from the normal trend can signal problems before the maximum allowable limits are exceeded. A valid trend of results is established after 3 consecutive samples that are performed within the recommended time/hours/km/fuel burn interval*

*It is important that oil sampling is performed at regular and pre-determined intervals (Note that your Owner’s Operation and Maintenance Manual should provide guidance on these intervals).

ICP (Inductively Coupled Plasma)

ICP is used to assess the type and quantity of elemental particles below 10 micron in size. For relativity, a human hair is approximately 80 micron thick and dust you can just see on your TV screen is about 40 micron in size.

Your William Adams S.O.S report will provide a parts per million (ppm) reading for 21 separate elements. Some customers will wish to look at these readings individually, whilst others will rely upon our S.O.S Interpreter’s knowledge, and the subsequent report comments and overall evaluation of the sample.

ICP provides an accurate wear metal analysis using a technique called plasma spectroscopy. This uses a flame-like plasma of very high temperature (6000-8000 degrees Celcius) to superheat the sample and provide rapid analysis in a single pass.

Our ICP utilizes energy from a radio frequency generator to excite argon gas to a plasma state. Your prepared oil sample is injected into the plasma where the atoms of the wear elements become thermally excited and emit light. The brightness of emitted light (the intensity) at a predetermined wavelength is proportional to the concentration of the element to which the wavelength is characteristic. In other words, each wear element (for example, Iron, Copper, etc) has a specific position on the electromagnetic spectrum (specifically its wavelength). The sensitive optical detectors within the ICP machine measure the light characteristics (namely the wavelength and brightness) of each wear element in the sample. . Your S.O.S report will provide the quantity of 21 different wear elements in ppm (parts per million).

What is ppm?

One particle of iron in 999,999 particles of oil or coolant is one ppm. To put this in perspective, it is comparable to:

1 second in 11.5 days

1 drop of ink in 150 litres of water

FTIR (Fourier Transform Infra Red)

Generally called infrared analysis (IR), this test determines the degree of used oil deterioration by measuring and quantifying soot, oxidation, nitration and sulphur products. It can indicate additive loss, and detect oil contamination from water and coolant (specifically ethylene glycol).

The FTIR can detect the presence of fuel, water and glycol contaminants in the oil. Water and fuel can then be further assessed using the Crackle Test and Setaflash respectively.

By monitoring the used oil condition, a more thorough indication of an impending failure and its cause may be identified. Infrared analysis answers some of the questions raised by wear metal analysis alone (e.g., the cause for bearing wear, ring sticking, transmission slippage, etc.). Interpretations are improved when infrared analysis is used as a diagnostic tool to help identify problems and their root causes.

Like most of our tests, the best results are obtained by performing infrared analysis on each sample and using trend analysis techniques. A deviation from the normal trend can signal problems before the maximum allowable limits are exceeded.

Contaminants result from outside sources or from chemical changes in the oil. Contaminants such as fuel, water, ethylene glycol, and soot are from outside sources. Oxidation and nitration are from chemical changes in the oil.

Sulphur products are also from a chemical change, but are created from normal contamination during the diesel engines combustion process. Below we will discuss each of these contaminants:

Water

Water may condense or leak into a compartment. Water can also be a result of pressure washing equipment. Equipment that operates in wet conditions may experience water in final drives and axles. Water can cause corrosive wear and rusting in any compartment. Corrosive wear occurs when the water combines with compounds in the oil to form acids. Rusting can occur in areas above the oil level in sumps, where an oil film does not protect the metal. If large quantities of water enter a compartment, the oil and water mixture could create a thick sludge.

Coolant

Contamination from ethylene glycol causes the oil to thicken. The sludge may cause the filter to plug and lead to other problems. Ethylene glycol acts as a catalyst, speeding up oxidation.

Engine oil may become contaminated with coolant due to leaks from: oil cooler cores, internal coolant passages, and cylinder head gaskets. Hydraulic systems or transmissions, using oil-to-water coolers, may become contaminated with coolant.

Contamination from ethylene glycol causes the oil to thicken. The sludge may cause the filter to plug and lead to other problems. Ethylene glycol acts as a catalyst, speeding up oxidation.

Soot

Soot is the insoluble residue of partially burned fuel. It is held in suspension by oil additives and causes engine oil to turn black. The soot particles are abrasive and cause engine wear.

As long as the soot particles are kept dispersed, they remain in suspension and cause little harmful effects Excessive soot levels will eventually overpower the engine oil additives. When this occurs, the soot particles will drop out of suspension and form larger particles. These larger soot particles will plug oil filters, form deposits, and increase oil viscosity. Eventually, engine wear will become abnormally high.

Soot generation is influenced by the following:

• Rack setting

• Air fuel ratio control

• Fuel nozzle operation

• Turbocharger operation

• Air cleaner operation

• Crankcase blowby

• Timing

• Engine operation (i.e., rapid acceleration lugging)

Oxidation:

The most commonly understood form of oxidation is rusting, or oxygen combining with iron. As with iron, oil oxidizes when oxygen joins the oil molecule. Oxidation is accelerated by high temperature, contaminants, and constant agitation.

As oil oxidizes, it loses its lubricating properties and forms resins. The most noticeable change is a thickening of the oil.

Oxidation is increased by:

• High temperature

• Exposure to air and/or air (oxygen) entrainment

• Catalysts such as ethylene glycol or copper

• Time oil is in use (extended oil change period)

Oxidation products can increase viscosity and cause filter plugging.

In diesel engines, an oxidized lubricant will lose the ability to protect components; as a result, piston rings may stick, cylinder bore polishing may occur and valves may scuff or stick.

In hydraulic systems, oxidized lubricants will increase pump wear and damage control valves. Powershift transmissions will experience clutch slippage, and abnormal wear if the oil is oxidized.

Sulfation

Sulphur is present in diesel fuel. During combustion, fuel sulphur combines with water to form sulphuric acid. Modern diesel engine lubricants are designed to neutralize this acid. However, if these acids reach unacceptable levels, the lubricant will be degraded and corrosion will occur. This corrosion can attack:

• Valves

• Valve guides

• Piston rings

• Cylinder liners

Nitration:

Although nitration occurs in all engines, it is a major consideration only in natural gas engines. The process begins in the combustion chamber where nitrogen oxides form from heat and pressure. Further reaction with fuel and oil results in nitrogen compound accumulations in the oil. These compounds cause deposits and thickening that interferes with lubrication.

Particle Count

Tracking the amount and build-up rate of large and small particles over time indicates the severity of system wear. Therefore, oil analysis must be capable of measuring a wide range of wear particles and contaminant particles.

Some types of wear produce particles that are extremely small. Other types of wear produce larger particles

that can be visually observed in the oil. Likewise, contamination particles come in a variety of sizes. Tiny particles of dust in the air can cause significant damage if the particles enter a lubricated compartment. Dirt from the soil will also cause damage if it is allowed to enter the lubricating oil.

To effectively measure this wide range of particle sizes, William Adams S·O·S laboratory uses two types of tests. The ICP test is used to quantitatively and qualitatively measure the extremely small particles. The Particle Count test is used to quantitatively measure the larger particles.

Particle Count analysis is used to evaluate particles larger than 10 microns, including non-metallic particles.

Particle Count results are listed as an ISO code (International Standards Organisation). The particle count test is performed per the procedure outlined in ISO4406. The Particle Count channel counts are reported in counts per millilitre of sample (counts/mL). An increase in ISO code values could indicate an increase in wear or the presence of contaminants.

A robotic optical particle counter is used in the William Adams S·O·S laboratory. The instrument shines a laser through the sample. A detector then counts the number and size of shadows created by particles in the oil. Any object in the oil that creates a shadow will be counted as a particle. Water droplets, entrained air and some oil additives will cause shadows. When water, air and additives are measured by a particle counter, it is called interference. It is not possible for the optical particle counter to distinguish the difference between shadows caused by debris and shadows caused by interference. Therefore, careful sample preparation and screening is required for best results.

Your particle count results will be displayed as 3 digits; for example: 20/18/15. Let’s refer to this as X/Y/Z. The X factor represents the number of particles larger than 4 microns. The Y factor represents the number of particles larger than 6 microns and Z factor indicates the number of particle larger than 14 microns

Under the ISO Code system 28 code numbers are set up, each representing a given range of particles per millilitre. The lowest number of particles per millilitre of sample is 0.01 and the highest number of particles per millilitre of sample is 2,500,000. Smaller code numbers correlate to smaller numbers of particles. Please note that the size of each code range is double the number of the preceding range.

Viscosity Test

Viscosity is a temperature dependent characteristic of lubricants that describes how the oil will flow. Our kinematic viscosity tests are conducted at 40 degrees Celsius by recording the time taken for the oil to cover a measured distance.

At high operating temperatures, a lubricant must be able to maintain appropriate film thickness. If the viscosity becomes too low, wear will occur within the compartment. If viscosity is too high, the oil will not flow to areas needing lubrication. Many diesel engine oils are designed with multi-grade viscosity characteristics. At low ambient temperatures, multi-grade oils have a lower viscosity to provide start up protection. At normal operating temperatures, the multi-grade oils have a higher viscosity to protect moving parts.

PQ (Particle Quantifier)

The PQ is designed to measure ferrous debris in lubricating oils. The PQ instrument exposes an oil sample to a magnetic field. If there are magnetic particles in the oil, the PQ records the change in the magnetic field. The result, of this measurement, is called the PQ index. The PQ index is proportional to the mass of ferrous particles in the oil.

The PQ has not been used as a replacement for an optical particle counter. Instead, the PQ has been used as a supplement to optical particle counting.

In many of these cases, an abnormal PQ value is accompanied by visible metal in the sample. The PQ analysis helps by placing a quantitative value to the visible metal.