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Once all of the tests are complete, a highly trained Data Evaluator evaluates the results. The evaluation will result in (1) a statement that the unit is normal, or (2) specific maintenance recommendations will be made. The report recommendations are only one tool that can assist you in making your maintenance decisions.



No explanation is needed for this category. Keep in mind that it is important to know that a unit is normal. This can save you unnecessary tear-down.


This category is followed by specific maintenance recommendations, or a notation that component wear is abnormal: there might, for example, be a recommendation to change oil and filters, and a comment noting that abnormal bearing wear is present. We are not telling you that it is time to tear down the unit. We are suggesting that you perform the maintenance suggested, and advising you that bearing wear is present. A second sample in a shorter time span might be requested. We do not recommend that you go into a unit on an abnormal recommendation unless you have discussed the report with the appropriate Laboratory Data Evaluator or you have indications that the unit has a more serious problem than is apparent in the report.   Again, your judgement must be based on all of the tools at your disposal, including our report, your knowledge of the unit and your experience.


This is the category we use to indicate potential failure and a serious condition exists. We will indicate the suspected nature of the problem and make a recommendation for maintenance action. Critical units require immediate attention.

Underlined Figures That Need Close Attention: A serious problem could be developing and the unit should be closely monitored.

Re-samples: We will request a second sample to establish a trend whenever we have a potential “critical” unit with no previous history. If the wear increases, you will be advised of the suspected nature of the problem.

In some cases, the data will identify an obvious problem. For example, a high level of water contamination along with high levels of boron and sodium is a good indication of antifreeze contamination. A high particle count and high levels of silicone usually indicate dirt or dust contamination, and the need to check air filters or breathers, reservoir access covers or oil storage and handling procedures.

Sometimes however, the analytical data from an individual sample does not provide enough information to make more subtle judgments about oil or equipment condition. In these situations it is necessary to monitor the trends in analytical data over a series of samples to establish a wear trend pattern. By monitoring wear metals such as iron, lead, copper, and tin it is possible to detect the early stages of possible bearing failure.   In most cases it can detect problem far enough in advance that it will allow for scheduling a bearing inspection at a convenient time, reducing or eliminating expensive equipment downtime and repairs.

One measure of the degradation of an engine is an increase in viscosity. Normally, a viscosity increase from one grade to the next is a warning that the oil has reached the end of its useful life.

Most engine oils are formulated with a variety of additives, which enhance lubricity, inhibit oxidation and corrosion and reduce the tendency for sludge and deposit formations. The levels of these additives can be determined by monitoring the Total Base Number (TBN), the reduction of a TBN below 3.0 is a warning that the additives have been depleted and an oil change should be scheduled. Some additive levels can be measured with spectrographic metals analysis. This test will detect the levels of zinc, phosphorus, calcium, and magnesium, which are common elements in most additive packages.

The most common engine oil contaminants are silicon (dirt), fuel dilution, and antifreeze coolant. Silicon (dirt) contamination is the most common form of contamination and causes serious engine wear due to its abrasive action against all moving parts within the engine. Silicon levels above 20ppm greater than the new oil should be considered cause for inspection of the air intake system to locate the source of entry for the dirt and other airborne debris.

Fuel dilution is serious since it can significantly reduce oil viscosity and lubricities thus causing engine wear. Fuel dilution can initially be detected by a lowering of the flash point of the oil, accompanied by a noticeable viscosity reduction, and a heavy fuel odor.

Coolant is another very common oil contaminant and probably the most serious. Water from the coolant reduces the lubricity, which causes severe bearing problems, while the glycol degrades at high temperatures and forms sludge. Monitoring water contamination levels is not reliable, since normal engine temperatures are high enough to evaporate the water over time and keep detectable levels as low as 0.05%. Coolant levels can be detected by chemical analysis and by monitoring the levels of boron, phosphorus, sodium and potassium in the oil.

Wear metal analysis can indicate which engine components are wearing and if the wear is becoming significant. This information can make the difference between minor component inspections and repairs and major overhauls. Wear metal levels are provided by spectrographic analysis of the oil sample, indicate the element level in parts per million (ppm), of each of the common metals found in the engine: iron, aluminum, chromium, lead copper tin, nickel and silver.

Wear metal analysis requires more than simply plotting data on a graph. Wear metals can be generated from as many as a dozen different engine parts and locations making it difficult to identify the specific part that is wearing excessively. It is the knowledge acquired through years of experience and analytical training, that the analyst can draw upon, to provide the most accurate analysis possible for customers.


Samples should ALWAYS be taken hot or just after shutdown to assure that all the particles are in suspension in the oil. Always clean around drain plug to avoid contamination. Taking samples from the same location each time will give uniform reports. When using sample pumps and tubing, make sure that a NEW piece of tubing is used for each sample. Oil Analysis spectrometers can only see particles under 10 microns. It is prudent for the oiler to visually check the oil flow for visible particles. Cutting open (with a filter cutter, not a hacksaw) filters and inspecting them can give evidence of immediate parts failure that oil analysis will not see because of the size of the particles. Keep the lids on the oil sample bottles until you are ready to fill them and cap them as soon as they are filled. Just dirty air can bring up the silicon count and give erroneous results.

A Quick Explanation of Anti-freeze Testing

Freeze point is the temp that the coolant will freeze at

% antifreeze is the antifreeze and water mix.  Typical should be 50/50

Nitrites are a chemical compound put in the antifreeze by the manufacturer to keep the system corrosion free. 

If this depletes there are additives that the end user can add to increase the  amount of nitrites, but this is typically not required nor recommended for new long life coolants

pH is the measure of the acidity.

Reserve Alkalinity is the measure of the ability of the fluid to neutralize acid similar to TBN’s in diesel engine oil.

Color, Green is usually conventional and any other color is usually long life.

Contaminants, This is what we see in a visual inspection looking for any contamination such as oil or other particles in the sample.

Spectrochemical Analysis – Wear Metals


Origin:                   Blocks, Gears, Rings, Roller Bearings, Cylinder Walls, Cylinder Heads, Rust

Purpose:              Because of its strength, iron is the base metal of steel in many parts of the engine. Since iron will rust, it is alloyed with other metals (i.e. Chromium, Aluminum, Nickel) making steel.


Origin:                   Shafts, Rings, Chromate from Cooling System, chrome plating on crankshafts.

Purpose:              Because of its strength and hardness, Chromium is used to plate rings and shafts that are usually mated with steel (softer). Chromium is also alloyed with iron (steel) for strength.


Origin:                   Bushings, Some Bearings, Pistons, Turbo Charger, Compressor Wheels

Purpose:              Aluminum is a strong lightweight metal (smaller mass) which dissipates heat well and aids in thermal transfer.


Origin:                   Bearings, Bushings, Oil Coolers, Radiators, Camshaft Thrust Washers, Connecting Rod Bushings, Oil Additive for Anti-wear/anti-oxidant, valve guides.

Purpose:              Copper is utilized to wear first in order to protect other components. Copper conforms well so it is used to seat bearings to the crankshaft.


Origin:                   Bearing Overlay, Oil Additive in Gear Lubes, Gasoline Contamination

Purpose:              Lead is a conforming material used to plate bearings. Lead will appear in new engines while the bearings are melding and conforming. If lead appears later, misalignment may be indicated


Origin:                   Valve Stems, Valve Guides, Ring Inserts on Pistons

Purpose:              Nickel is alloyed with iron in high strength steel used to make valve stems and guides


Origin:                   Bearing Cages (low friction bearings), Silver Solder, Turbocharger bearings and wrist pin bushings

Purpose:              Silver is used to plate some components because it conforms well, dissipates heat and reduces coefficient of friction.

TIN (Sn)

Origin:                   Bearings, pistons

Purpose:              Tin is a conforming material used to plate and protect surfaces to facilitate break-in.


Origin:                   Piston rings, oil additives

Purpose:              Molybdenum is used as an alloy in some piston rings in the place of Chromium. Molybdenum is also used as a friction-reducing additive in some oils. Soluble Molybdenum can be used as an antioxidant additive.

Spectrochemical Analysis – Additive Elements


Purpose:              Anti-wear additive, which provides a protective film.


Purpose:              Anti-wear, Extreme Pressure additive that provides a protective film in high-pressure areas, Antioxidant Phosphorus is added to extreme pressure oils to provide a protective film.  Extreme Pressure oils are characterized by high phosphorus.


Purpose:              Detergent: Barium is toxic and expensive but it is advantageous because it does not leave excessive ash residue.


Purpose:              Calcium and Magnesium are alkaline-based additives used to neutralize acids formed by products of combustion in engine oils.  Calcium and Magnesium also have some detergent qualities.


Purpose:              Inhibitor - Boron is also found as an additive in coolant as borate. Also an additive in some gear oils.


Purpose:              Antioxidant Copper is added to engine oils to prevent oxidation.

Spectrochemical Analysis - Contaminants


Origin:                   Potassium is a coolant additive and its presence in oil is indicative of coolant contamination. Also, present as an additive in some gear oils.


Origin:                   External contamination, additive or coolant.  Sodium is not a wear metal.  Its source is from coolant or the environment (salt) and or salt water.


Origin:                 External (dirt), Additive, Sealant's.  Silicon can be an anti foam additive in the form of silicone.

Sample Results Troubleshooting


Fuel dilution of crankcase oil by unburned fuel reduces lubricant effectiveness. The thinning of lubricant can lead to decreased lube film strength adding to the risk of abnormal wear.  Depending on certain variables, when fuel dilution exceeds 2.5% to 5%, corrective action should be taken.  Both gas chromatography and fuel dilution meters measure fuel dilution.



Incorrect air to fuel ratio

Metal to metal contact

Extended idling

Poor lubrication

Stop and go driving

Cylinder ring wear

Defective injectors

Depleted additives

Leaking fuel pumps or lines

Decreased oil pressure

Incomplete combustion

Reduced MPG

Incorrect timing

Reduced engine performance


Shortened engine life


  1. Check fuel lines, worn rings, leaking injectors, seals, and pumps

  2. Examine driving or operating conditions

  3. Check timing

  4. Avoid prolonged idling

  5. Change oil and filters

  6. Check quality of fuel

  7. Repair or replace worn parts


Viscosity is one of the most important properties of lubricating oil. Viscosity is a measurement of resistance to flow at a specific temperature in relation to time.  The two most common temperatures for lubricating oil viscosity are 40°C and 100°C.  Viscosity is normally evaluated by a kinematic method and reported in centistokes (cSt).  In used oil analysis the used oil’s viscosity is compared to that of the new oil to determine whether excessive thinning or thickening has occurred.

High viscosity

Low Viscosity

Contamination soot/solids

Additive shear

Incomplete combustion- A/F ratio

Fuel dilution

Oxidation degradation

Improper oil grade

Leaking head gaskets

Mixing of Oils

Extended oil drain


High operating temperature


Improper oil grade


Mixing of oils



High Viscosity

Low Viscosity

Increased operating costs

Engine overheating

Engine overheating

Poor lubrication

Restricted oil flow

Metal to metal contact

Oil filter by-pass

Increased operating costs

Harmful deposits or sludge




  1. Check air to fuel ratio

  2. Check for incorrect oil grade

  3. Inspect internal seals

  4. Check operating temperature

  5. Check for leaking injectors

  6. Change oil and filter

  7. Check for loose fuel crossover lines



Water presence in engines indicates contamination from outside sources. These sources may be condensation of moisture from the atmosphere, or from internal water leaks.  Engines at normal working temperatures normally evaporate water.  However, water may remain in the oil when engine temperatures are to low for evaporation to occur.  Other types of equipment, when operated at satisfactory temperatures also have a tendency to evaporate water contamination.

Oil analysis can identify water/coolant contamination before a problem occurs. ASTM D-6304, the Karl Fischer method is used to measure water in systems, which are sensitive to low moisture content.




Low operating temperature

Engine failure

Defective seals

High viscosity

New oil contamination

Poor lubrication         

Coolant leak


Improper storage

Increased engine heat

Cracked head

Acid formation


Weld spots

Product of combustion

Reduced additive effectiveness


  1. Tighten head bolts

  2. Check head gaskets

  3. Inspect heat exchanger and oil coolers

  4. Evaluate operating conditions

  5. Check for external sources

  6. Change oil filters

  7. Pressure check cooling system




Solids represent a measurement of all solid and solid-like material in a lubricant. The makeup of solids depends on the system.  In diesel engines fuel soot is usually the major component measured.  In non-diesel components wear debris and oil oxidation products are measured.



Extended oil drain intervals

Shorter engine life

Environmental debris

Filter plugging

Wear debris

Poor lubrication

Oxidation by-products

Engine deposits

Leaking or dirty filters

Formation of sludge

Fuel soot

Accelerated wear Decreased oil flow


  1. Drain oil

  2. Flush system

  3. Change operating environment

  4. Reduce oil drain intervals

  5. Change filters



Total Base Number (TBN) represents the amount of alkaline additives in the lubricant which neutralizes the acidic products of combustion.



High sulfur fuel

Decrease of total base number oil degradation


Increased wear rate

Extended oil drain

Acid build up in oil

Improper oil type



  1. Use low sulfur diesel fuel

  2. Re-evaluate oil drain intervals

  3. Verify total base number of oil being used

  4. Change oil

  5. Test fuel quality




Total Acid Number (TAN) is the quantity of acid or acid-like derivatives in the lubricant.  An increase in TAN from that of the new lubricant should be monitored. The TAN of a new oil is not necessarily nil since oil additives can be acidic in nature.  Increases in TAN usually indicate lubrication oxidation or contamination with an acidic product. TAN is an indicator of oil serviceability.



High sulfur fuel

Corrosion of metallic components (especially soft metals such as bearings)


Promotes oxidation

Excessive blow-by

Oil degradation

Extended oil drain intervals

Oil thickening

Improper oil type

Additive depletion



  1. Drain oil

  2. Reduce oil drain intervals

  3. Confirm oil type being used

  4. Check for overheating

  5. Check Fuel Quality




Fuel Soot is formed of carbon and is always found in diesel engine oil. Laboratory testing is used to determine the quantity of fuel soot in used oil samples.  Recent EPA emission regulations have placed greater importance on fuel soot levels.  The fuel soot level is a good indicator of engine combustion efficiency and should be monitored on a regular basis.



Improper air/fuel ratio

Poor engine performance

Improper injector adjustment

Poor fuel economy harmful deposits or sludge increase wear

Poor fuel quality

Carbon deposits

Incomplete combustion

Clogged filters

Low compression


Worn engine parts/rings




  1. Ensure injectors are working properly

  2. Check air induction/filters

  3. Change oil

  4. Assess oil drain intervals

  5. Check compression

  6. Avoid excessive idling

  7. Inspect driving and operating conditions

  8. Check fuel Quality




Lubricating oil in engines and other components will combine with available oxygen under certain conditions to form a wide variety of harmful by-products. Heat, pressure and catalyst materials accelerate the oxidation process.  By-products of oxidation form lacquer deposits corrode metal parts and thicken oil beyond its ability to lubricate. Most lubricants contain additives, which inhibit or retard the oxidation process.  Differential infrared analysis is the method used to measure the level of oxidation in used oil. 




Shortened equipment life

Extended oil drain intervals

Oil filter plugging

Improper oil type/inhibitor additives

Increased viscosity

Combustion by-products/blow-by

Corrosion of metal parts


Increased operation expenses


Increased wear rate


Decreased engine performance



  1. Use oil with oxidation inhibitor additives

  2. Shorten oil drain intervals

  3. Check operating temperatures

  4. Check quality of fuel




Nitration products are formed during the fuel combustion process when combustion by-products enter the engine oil during normal operation or as a result of abnormal blow-by past the compression rings. These products are highly acidic, create deposits and accelerate oil oxidation.  Infrared analysis represents the only method of accurately measuring nitration products in used oil.




Improper scavenge

Accelerated oxidation

Low operating Temperatures

Nitrous oxides introduced into the system

Defective seals

Acidic by-products

Improper air/fuel ratio

Increased cylinder wear

Abnormal blow-by

Oil thickening


Combustion deposits


Increased total acid number



  1. Increase operating temperature

  2. Check Crankcase venting hoses and valves

  3. Ensure proper air/fuel mixture

  4. Perform compression check




Particle Count testing basically measures the relative cleanliness of a given fluid. It is primarily used for hydraulic and turbine systems to evaluate the effectiveness of the filters. It has been proven that reducing the particulate debris in the fluid can greatly increase the life of these systems. 

The instrument that is normally used is a Parker Hannifin Particle Counter that measures the total population of particles in different size ranges. High levels of water can produce erroneously high readings.  After the analysis is completed, and ISO Cleanliness Rating is determined from the results.  The ISO Cleanliness Rating consists of three numbers and is a convenient method to communicate the sometimes-unwieldy particle results.  The first number represents 4-micron (silt) particles.  The second number represents 6-micron (silt) and the (abrasive) particles, and the third number represents the 14 micron (abrasive) Particles.



Water contamination

Increased wear

Oil oxidation

System Failure

Worn seals

Equipment Failure     

Ineffective filtration

Plugging and/or leakage

Dirty make up oil

Pressure pulsing        


Sluggish valves or actuators


  1. Change filter

  2. Change Oil

  3. Use higher quality filters

  4. Insure integrity of seals


Typical fluid cleanliness levels for hydraulic components:

Component types




Servo Valves




Vane and Piston Pumps




Directional and pressure




Control Valves




Flow control valves and











Data Acquisition: In order to assign an ISO Cleanliness Rating to represent the contamination level of a fluid, the number of particles greater than 6 micron and 14 micron unit volume must be available.  Furthermore, the particle population must be obtained from a particle counting system, which has been calibrated per ISO/DIS 4406:1999, or an ISO approved equivalent method in order to assign a valid cleanliness rating.  The actual counting system is immaterial as long as the acceptable calibration certification is available.

Particle Concentration

(Particles per millileter)

Range Number

10 000 000


5 000 000


2 000 000


1 300 000


640 000


320 000


160 000


80 000


40 000


20 000


10 000