S.O.S Process

S.O.S Process


Lab Tour

More than an oil laboratory...Zahid S·O·S Fluid Analysis labs combine high tech fluid analysis with an in depth mechanical understanding and technical resources that only a focused mechanical equipment company can provide. Our Lab provide complete oil-fuel-and coolant analysis services for all types of mobile and stationary machinery. This wide range of standard and specialized testing and detailed interpretation of results is carried out to exacting standards in our ISO 9002 Registered facilities. Our goal is to keep your machinery productive and your costs down.

Come and join us for a tour of some of the basic parts of this process...

Sample Arrive

Your samples arrive at our lab via Express Post Courier, via our branch network through Zahid Henour Parts Express trucking system, or our drop box located outside each branch.



Upon arriving at the lab the samples are opened and registered into the lab's information management system.

The information which you have provided regarding your name and location, the machine and compartment being sampled, the oil information, and other details are carefully transferred into the system from the test request form.

In the case of samples which have been pre-registered using the oil lab web-site the sample label numbers are compared to the numbers that you have provided to ensure that each sample is fully identified.

Particle Quantifier

While the emission spectrometer is a highly accurate instrument for measuring normal wear it is not effective for detecting the larger debris that would be produced by bearing and gear fatigue in geared compartments such as powershift transmissions, differentials, and final drives.

Furthermore, it can not quantify in a meaningful fashion the amount of solid oil contaminants that will lead to accelerated wear.


Particle Counter

Samples requiring a complete electronic particle then move to the particle count area where they are agitated to suspend the particles. The sample is then placed in an ultrasound to remove any air bubbles and then drawn through the laser diode of the particle counter which measures the amount of debris contained in the oil in eight size ranges from 5 to 100 microns.

The ISO cleanliness code is also calculated. As a final step the debris in the oil is deposited on a slide for microscopic examination and identification of the debris. A picture is taken to be included with the report.


Infrared Analysis

The next stage of the process involves checking oil condition through the use of an Infrared Spectrometer. Hydrocarbon molecules react to the infrared radiation by absorbing the energy at different wavelengths. By measuring this absorbance in addition to the total transmitance a determination of oil condition can be made. Your engine oils are checked for the soot loading which has occurred in addition to chemical changes of Oxidation and Sulfation (diesel engines) and Nitration and Oxidation (gas engines). Due to the nature of their application hydraulic and transmission oil samples are checked for Oxidation only.



The first step in the analytical process is to determine the viscosity of the used oil at 40C.

The viscosity is measured using a computer controlled viscometer.

This is a very important initial step as the viscosity of the used fluid should still be in the same range as it was when the fluid was new.

If a substantial variance in these viscosity readings is noted it is the first indication that a problem may exist.

Flash Point Test

If a viscosity drop in an engine oil sample has occurred or if any other condition is noted that could suggest fuel dilution, the oil will be heated in a flash tester to determine whether excessive fuel is present.

Excessive fuel dilution can destroy the ability of the oil to form a protective film and connecting rod bearing damage is likely.

Generally the lower the temperature that the oil vapor will flash the more fuel is present in the sample.


Water Test

Next the sample is checked for water by placing a small amount of oil onto a constant temperature hotplate. If water is present the water will begin to boil and will form bubbles within a few seconds. Water does not act as a good lubricant and even relatively small amounts can interfere with the oil's ability to form a protective film between moving parts.(You can actually perform this test in your shop by dropping a few mils of oil on a surface which is slightly above the boiling point of water)

Water is one of the two most widespread and destructive contaminants in lubricants, second only to solid particulate contamination. Damage resulting from water contamination is not as immediately noticeable as it is from particle contamination but, it can be more systemic. Water found in lubricants can enter in a number of ways and will be present in the form of dissolved, emulsified (suspended as the internal phase of a water-oil emulsion) or free water. Water can gain access to lubricant systems through improper vents, defective seals or other housing openings, from internal heat exchangers or oil coolers that are leaky or corroded. Water is a normal combustion product, and blow-by exhaust gases from combustion processes can ali systems.

New lubricants may be contaminated with some level of water when they are delivered from the manufacturer. Water can exist in new oil as a result of refining, manufacturing or blending operations. Water can also be introduced from inadequate transport procedures, handling practices or storage conditions from the supplier. Bulk delivered lubricants will be more susceptible to this than drum supplied lubricants.

The presence of water in oil can cause corrosion, excessive wear, and premature failure lubricated metal surfaces. Water can act directly on metal surfaces and it also impairs lubricant effectiveness. Presence of water can also modify the physical properties of the oil. Since the viscosity of water does not increase with pressure like that of lubricants, water in oil can decrease the effective lubricant viscosity resulting in insufficient elastohyrodynamic film thickness and inadequate fluid-film strength. An increase of oxidation is also caused by water. Lubricant additive properties can also be affected by water. Water changes the solubilization characteristics of the lubricant. Some additives may become de-solubilized which contributes to sludge formation. Other additives may be preferentially solubilized by water and washed out. Water can also react with some additives making them chemically unavailable and transforming them into harmful materials such as acids or sludge.

Wear Metals

We use Perkin Elmer ICP's to perform elemental analysis. The spectrometer determines elements in a sample by subjecting the oil to very high temperatures.

At these temperatures the elements in the samples are "atomized" with each emitting a different wave length of light energy.

An optical system measures and records the light energy and calculates the results in ppm (parts per million) for each element.


Optional Tests

Samples which require optional tests such as Total Base Number (TBN), Total Acid Number (TAN) and Karl Fischer Water determination (KFW) are moved to the titration area for this part of the analysis.

TBN (Total Base Number) - This method determines the reserve alkalinity of a lubricant. The base number is an indicator of the oil's ability to neutralize acidic compounds formed by oxidation processes. Oil changes are indicated when the base number reaches a predetermined level for a given lubricant and application.

TAN - (Total Acid Number) - The TAN of oils will change due to additive depletion, oxidation, and nitration. This test is to give some indication of the degree of oxidation and nitration that has taken place.

KFW - (Karl Fischer Water) - Measure of moisture in the oil. Water does not act as a good lubricant and even relatively small amounts can interfere with the oil's ability to form a protective film between moving parts.

Coolant Analysis

Level 1: verification of coolant properties

B Glycol % (refractometer), nitrite % (titration).

Precipitate Identification acidity (pH meter)
total dissolved solids
(conductivity meter)

Physical attributes
appearance, color, odor


Fuel Contamination

The amount of solid contamination contained in the fuel is measured by filtering the fuel through a membrane and recording the resulting weight gain.


Following completion of this analytical process the data is reviewed by a team of trained interpreters who make the determination concerning machine and oil condition.

Their commentary and recommendations form a major part of the final report. In the event that a problem is found that appears urgent the interpreter will contact the owner of the machine to discuss the situation and alert the customer to the situation.

We hope that you have enjoyed this tour of our Fluid Analysis Lab.



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For more information, please contact us, or call our Toll Free: 800 2 444 999, Telephone: +966 12 6833542,

Email: inquiry@zahid.com