FAQ – Oil Analysis

What is oil analysis?

Oil analysis is a diagnostic, preventive maintenance tool for monitoring and evaluating lubricant and equipment conditions. It allows you to see what’s happening in your equipment before failure.

Why should I do oil analysis?

Oil analysis allows you to maximize asset performance and reliability by identifying minor problems before they become major failures. It can safely extend oil drain intervals and, ultimately, the life of your equipment — saving you time AND money.

How do I take a sample of my oil?

Consult our list of sampling equipment and supplies to determine what sampling system and procedure will work best for the type of equipment you want to test. For step-by-step instructions by sampling equipment type, click on How to Take a Sample.

How often should I sample my oil?

Although the original equipment manufacturer’s recommendations provide a good starting point for developing preventative maintenance practices, sampling intervals can easily vary. How critical a piece of equipment is to production is a major consideration for determining sampling frequency, as are environmental factors such as hot, dirty operating conditions, short trips with heavy loads and excessive idle times.

Can oil analysis predict equipment failure?

Yes. Oil Analysis provides vital information as to the condition of both the oil and the unit being tested. It can detect wear and contamination problems that, if left unchecked, can severely effect equipment performance or cause failure.

What are the most common oil analysis tests?

Elemental Analysis by ICP
Inductively Coupled Plasma, detects 24 wear, contamination, and additive metals.

Fuel Dilution
Fuel Dilution is raw, unburned fuel that gets past the rings and ends up in the crankcase. It is caused by over-fueling, excessive idling, damaged injector tips, a high fuel to air ratio, irregular ring seating, engine timing issues or the fuel pump is turned up too high.

Soot is a by-product of the combustion process in a diesel engine — a carbon residue formed from fuel air and moisture in the combustion chamber after ignition. Soot particles are held in suspension by dispersant additives in the oil preventing the soot particles from agglomerating (sticking together) and attaching to the rings, pistons and liners. These suspended particles are what turn diesel engine oil black. When too much soot is generated and the additives can no longer keep it suspended, deposits will form on the rings weakening the seal between the pistons and cylinder liners. Upper end wear to rings, liners and pistons begins and if not corrected, will eventually cause severe lower end wear to the main and rod bearings, crankshaft, camshaft, cam bushing and turbo bearing.

Water by Crackle
This is a rough estimate of water in a sample determined by pipetting a portion of sample onto a temperature-controlled hot surface and observing how the sample reacts.

Viscosity is a measurement of a fluid’s resistance to flow at temperature. In other words, viscosity is the film strength or thickness of the oil. A change in viscosity can be an indication of many problems such as oxidation, nitration, water contamination, soot contamination (engines), shearing (when molecules are split), coolant contamination or mixing lubes with different viscosities.

Everything that is exposed to oxygen will eventually oxidize. Oil is exposed to extreme heat as well as oxygen. As temperatures increase, so does the rate of oxidation. For every 18° F above 160° F, the oxidation rate of the oil doubles. Oxidation produces acids that cause the oil to thicken and in the process also cause corrosive wear.

Nitration is usually the result of an imbalance in the engine’s air to fuel ratio. When the engine runs too lean, meaning there’s too much air and not enough fuel, nitration occurs. Nitrous Oxide (NOx) becomes entrained in the oil which can form nitric acid that will eventually will lead to corrosive wear. Although nitration is more common in natural gas engines, it has become a more evident problem in diesel engines since 2002.

Acid Number
By estimating the amount of additive reduction and contamination, this test determines the level of acidity in the oil. The higher the acidity, the higher the degradation.

Base Number
This test estimates the lubricant’s reserve alkalinity, or its ability to neutralize corrosive and degradation acids.

Particle Count
This test uses a calibrated sensor to size and count hard particle contamination.

Particle Quantifier
Particle Quantifier (PQ) provides a ferrous index number by passing a sample through a magnetic field. Comparing PQ to the iron results from ICP gives more information regarding the size of the iron particles being generated as PQ does not have a particle size detection limit.

Analytical Ferrography
Debris from a fluid analysis sample is examined under a microscope to identify the size and wear mechanism of particles being generated, which provides more information for pin-pointing the cause of a failure mode.

Water by Karl Fischer
A titration method that tests for water content. This method is more precise than hot plate and should be requested for any system in which water would be severely detrimental.

For more test methods performed at POLARIS Laboratories®, download our complete test list.

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