OIL ANALYSIS

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Oil Analysis History
The first use of used oil analysis dates back to the early 1940s by the railway companies in the Western United States. Prompted by the purchase of a fleet of new locomotives, technicians used simple spectrographic equipment and physical tests to monitor locomotive engines. As steam locomotives gave yield to diesel locomotives, oil analysis practices by railways caught on. By the 1980s oil analysis formed the basis of Condition Based Maintenance in most railways in North America.

Owing to the success of oil analysis in the railways, the American Navy used spectrometric techniques to monitor jet engines on their aircraft in the mid 1950s. Around this time Rolls-Royce was also experimenting with oil analysis for their jet turbines. Oil analysis began to spread and programs were developed by the American Army and Air Force throughout the 1950s and early 1960s. Then commercial oil analysis laboratories first appeared on the scene in the early 1960s.



A detailed analysis of a sample of engine, transmission and hydraulic oils is a valuable preventive maintenance tool . In many cases it enables identification of potential problems before a major repair is necessary, has the potential to reduce the frequencies of oil changes, and increases the resale value of used equipment.



What is Oil Analysis?
Oil analysis involves sampling and analyzing oil for various properties and materials to monitor wear and contamination in an engine, transmission or hydraulic system. Sampling and analyzing on a regular basis establishes a baseline of normal wear and can help indicate when abnormal wear or contamination is occurring.
Oil analysis works like this. Oil that has been inside any moving mechanical apparatus for a period of time reflects the exact condition of that assembly. Oil is in contact with engine or mechanical components as wear metallic trace particles enter the oil. These particles are so small they remain in suspension. Many products of the combustion process also will become trapped in the circulating oil. The oil becomes a working history of the machine.

Particles caused by normal wear and operation will mix with the oil. Any externally caused contamination also enters the oil. By identifying and measuring these impurities, you get an indication of the rate of wear and of any excessive contamination. An oil analysis also will suggest methods to reduce accelerated wear and contamination.

The typical oil analysis tests for the presence of a number of different materials to determine sources of wear, find dirt and other contamination, and even check for the use of appropriate lubricants.



Oil analysis can detect:
Fuel dilution of lubrication oil
Dirt contamination in the oil
Antifreeze in the oil
Excessive bearing wear
Misapplication of lubricants
Some wear is normal, but abnormal levels of a particular material can give an early warning of impending problems and possibly prevent a major breakdown.


Early detection can:
Reduce repair bills
Reduce catastrophic failures
Increase machinery life
Reduce non-scheduled downtime
Early detection with oil analysis can allow for corrective action such as repairing an air intake leak before major damage occurs. Probably one of the major advantages of an oil analysis program is being able to anticipate problems and schedule repair work to avoid downtime during a critical time of use.


Looking Inside
One purpose of oil analysis is to provide a means of predicting possible impending failure without dismantling the equipment. A person can "look inside" an engine, transmission or hydraulic systems without taking it apart.


Evaluating Used Equipment
A complete record of oil analysis may be a great tool for selling a used piece of equipment. It shows the potential buyers how the equipment has been maintained and how adjustments were made during its life. The history is a good indicator of potential future repairs and overhaul requirements.
One potential use of oil analysis is in the evaluation of used equipment being considered for purchase. Without knowing the amount of operation of the oil being analyzed, this test should be considered conclusive only if it indicates a problem. A good report could result from either no problems or a short length of service of the oil.



Physical Tests
Some of the physical properties tested for and usually included in analysis of an oil sample are:


Antifreeze forms a gummy substance that may reduce oil flow. It leads to high oxidation, oil thickening, high acidity, and engine failure if not corrected.
Fuel dilution thins oil, lowers lubricating ability, and might drop oil pressure. This usually causes higher wear.
Oxidation measures gums, varnishes and oxidation products. High oxidation from oil used too hot or too long can leave sludge and varnish deposits and thicken the oil.
Total base number generally indicates the acid-neutralizing capacity still in the lubricant.
Total solids include ash, carbon, lead salts from gasoline engines, and oil oxidation.
Viscosity is a measure of an oil's resistance to flow. Oil may thin due to shear in multi-viscosity oils or by dilution with fuel. Oil may thicken from oxidation when run too long or too hot. Oil also may thicken from contamination by antifreeze, sugar and other materials
.
Metal Tests
Some of the metals tested for and usually included in analysis of an oil sample and their potential sources are:


Aluminum (Al): Thrust washers, bearings and pistons are made of this metal. High readings can be from piston skirt scuffing, excessive ring groove wear, broken thrust washers, etc.
Boron, Magnesium, Calcium, Barium, Phosphorous, and Zinc: These metals are normally from the lubricating oil additive package. They involve detergents, dispersants, extreme-pressure additives, etc.
Chromium (CR): Normally associated with piston rings. High levels can be caused by dirt coming through the air intake or broken rings.
Copper (CU), Tin: These metals are normally from bearings or bushings and valve guides. Oil coolers also can contribute to copper readings along with some oil additives. In a new engine these results will normally be high during break-in, but will decline in a few hundred hours.
Iron (Fe): This can come from many places in the engine such as liners, camshafts, crankshaft, valve train, timing gears, etc.
Lead (Pb): Use of regular gasoline will cause very high test results. Also associated with bearing wear, but fuel source (leaded gasoline) and sampling contamination (use of galvanized containers for sampling) are critical in interpreting this metal.
Silicon (Si): High readings generally indicate dirt or fine sand contamination from a leaking air intake system. This would act as an abrasive, causing excessive wear. Silicon is also used as a anti-foam agent in some oils. MORE ON SILCON
Sodium (Na): High readings of this metal normally are associated with a coolant leak, but can be from an oil additive package.
Taking an Oil Sample
It is important to get an oil sample that is representative of all of the oil in the machine. Remember, your analysis will be based only on the sample that you send in for analysis. Always have the oil hot and thoroughly mixed before sampling. Handle hot drained oil with care — it could cause serious burns.
The easiest way to obtain a sample may be when the oil is being drained for an oil change. Sampling at this time usually involves letting some of the oil drain and then catching a sample in an appropriate container.

Samples also can be obtained without draining oil by suctioning out through plastic tubing routed down into the oil reservoir.

In any case, it is important to have an appropriate container and follow sampling directions thoroughly. Remember, many of the tests are for measuring materials on a parts per million basis, so safe, effective sampling is needed.



Cost and Convenience
Cost of oil analysis will vary according to the laboratory and extent of the analysis. Typical charges are $10 to $30 per analysis. The expense easily can be justified if it alerts the owner of a major problem that can be corrected and will help prevent downtime when the machine is needed.
Several companies have developed oil analysis kits that make oil analysis convenient. These kits include the sample bottles, suction pump and tubing, and possibly a pre-addressed, postage-paid mailing container.

The reasonable cost and convenience of oil analysis for use makes it another management tool that should be considered by anyone wanting to do preventive maintenance. .



Results
Results of the laboratory analysis are typically returned in two to seven days after the lab receives the sample. Results are returned to the owner for review. The laboratory may note when the analysis shows an abnormal condition and issue a caution or recommendation accordingly (Figure 1).
A typical analysis report is included in Table I. It shows how detection can predict engine problems. Other typical recommendations might be:



Example 1: Bearing metals indicate wear Inspect all bearing areas for wear Resample at 1/2 interval
Example 2: Unit is in satisfactory condition Resample at normal interval
Example 3: Abrasion indicated Inspect air filtration system Upper cylinder wear indicated Excessive fuel dilution Resample at 1/2 interval
Optimum Maintenance Interval
Most maintenance experts realize the oil change intervals for both engines and transmissions are decided by the "average need." No two pieces of equipment have the same preventive maintenance needs. Each machine has different imperfections and is used under different conditions. Operators doing smaller or lighter jobs can cause different conditions on engines and transmission wear than those that occur during more extended use. When using oil analysis to determine maintenance intervals, there is little guesswork. Records show that some equipment can safely run two or three times longer than recommended intervals. The oil analysis may show that you are changing the oil more often than necessary — or not often enough.
By eliminating too frequent oil changes, you reduce the cost for oil and servicing and also reduce the amount of used oil to deal with. This is an important pollution prevention method — reducing the source!

Oil sample analysis saves you repair and maintenance dollars, has the potential to reduce used oil and increases resale value of equipment.

These are average numbers used but depending on your type of equipment may be higher or lower. Most reports have charts listed on the back to explain the severity of that component in ppm.

Table I. Engine problems predicted with oil analysis.

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Indicator Acceptable Levels Engine Problem What to Check

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Silicon (Si) and
Aluminum (Al) 10 to 30 ppm Dirt ingestion Air intake system, oil filter plugging, oil filler cap and breather, valve covers, oil supply
Iron (Fe) 100 to 200 ppm Wear of cylinder liner, valve and gear train, oil pump, rust in system Excessive oil consumption, abnormal engine noise,performance problems, oil pressure, abnormal operating temperatures, stuck/broken piston rings
Chromium (CR) 10 to 30 ppm Piston ring wear Excessive oil blow-by and oil consumption, oil degradation
Copper (CU) 10 to 50 ppm Bearings and bushings wear, oil cooler passivating,radiator corrosion Coolant in engine oil, abnormal noise when operating at near stall speed
Lead (Pb)* 40 to 100 ppm Bearing corrosion Extended oil change intervals
Copper (CU) and
Lead (Pb)* 10 to 50 ppm Bearing lining wear Oil pressure, abnormal engine noise, dirt being ingested in air intake, fuel dilution, extended oil drain intervals
Aluminum (Al) 10 to 30 ppm Piston and piston thrust bearing wear Blow-by gases, oil consumption, power loss, abnormal engine noise
Silver and
Tin 2 to 5 ppm
10 to 30 ppm Wear of bearings Excessive oil consumption, abnormal engine noise, loss in oil pressure
Viscosity Change
Lack of lubrication Fuel dilution, blow-by gases, oil oxidation, carburetor choke, ignition timing, injectors, injector pump, oil pressure
Water/Anti-freeze
Coolant leak or condensation Coolant supply, gasket sealed, hose connection, oil filler cap and breather

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* Significant as wear metal, only for engines using unleaded and diesel fuel.
 
Great post Bob.

I just wish that oil analysis was done more often here in europe by car owners. As far as I can tell nobody analyzes their oil, not even me
rolleyes.gif
, it is just not that common as in the US.

John
 
Another way to sample oil that I don't think you mentioned is to install an oil sampling valve (an example is shown

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or search Google for "oil sampling valve"). I'm planning to put one in at the junction for the oil pressure sending unit. It's not the absolute best way to do it since there is some likelihood of external contamination, but it has several advantages - it's cleaner than doing it mid-drain, it doesn't require you to drain the oil to analyze it (nice if you have a bypass filter or other extended-drain solution), and it's a lot easier than figuring out how to get a tube and suction down into your oil pan.

[ October 13, 2002, 10:42 AM: Message edited by: BOBISTHEOILGUY ]
 
Good point Alex...

You also can use a siphon pump to draw samples through the dip stick..
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To use this type of application...
Sampling Procedure (Vacuum Pump)
With the engine shut off, insert the two (2) meter piece of clean plastic tubing through the head of the sampling gun.
The tubing should be cut at a 45° angle for easy insertion through the cap.
Next, tighten the sampling bottle onto the cap of the vacuum pump.
For compartments with a dipstick, the tubing should be cut to the length of the dipstick.
For compartments without a dipstick, such as gearboxes, final drives and other fixed or mobile equipment, the tubing should be cut to length as necessary.
Several light pulls of the handle will fill the bottle.
In order to obtain a homogenous sample it is essential that the oil be at operating temperature.
The tubing must be used only once and then discarded.
When you discard the tubing, do not pull the tubing back through the top of the pump, as this could contaminate subsequent samples. Instead, cut the tubing just above the top of the pump, and then pull the remaining piece (that was in the bottle) from the bottom of the pump.

You can get these from wear check, amsoil, and even schaeffers has them.

The most common method is the downstream method pulling directly from the pan..
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Sampling Procedure (Drain Stream Method)
All dirt and debris from around the drain plug must be cleared before the sample is taken. Compressed air can be used for this.
Remove the drain plug and allow the oil to start draining.
Once the flow is clear of visible debris the bottle can be placed under the flow and filled to the recommended level.
This bottle must be capped immediately.
Do not take the oil sample from the drain container!

another one is the drain plug..
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Install this valve and you can drain your engine oil without tools and without mess. Just lift the lever of this solid brass ball valve and give it a quarter turn to open it. Return the lever to its original position and it locks closed, double sealed to prevent leakage. This is called a Fumoto Engine Oil Drain Valve. Fram has something simular at autozone.
 
John,

I air mail oil analysis sample kits to a customer of mine in Germany ....He air mails the Oil samples to Oil Analyzers in Wisconsin and they send me the paper test results. I then mail those to Klaus and he gets his data, usually within 3 weeks and when he first sends the oil sample. We have been testing some of the" ARAL" 0w-40 synthetic in VW Polo and Audi diesel engines specifically ....

Works like a charm
smile.gif


TooSlick
 
Thanks for figuring out the pictures; I would like to use the dipstick suction method, but on my Toyota Matrix the dipstick tube is extremely narrow.
 
quote:

Originally posted by alexiskai:
Thanks for figuring out the pictures; I would like to use the dipstick suction method, but on my Toyota Matrix the dipstick tube is extremely narrow.

I sampled a friends Saturn that had a dipstick tube that was too narrow to accept the 1/4" O.D. tubing I had. The tubing just fit into the dipstick tube, but then passed through some type of constriction just before the oil pan so the tubing stopped just short of where it needed to be.

What I finally did was find 3/16" O.D. tubing that fit nicely into the 1/4" O.D.. It turns out the I.D. of the 1/4" O.D. tubing was just shy of 3/16" and made a nice vacuum tight fit.

I also got 1/8 O.D. tubing that would fit into the 3/16 O.D. tubing in case I really needed it (so I could have gone 1/4" to 1/8" if I wanted).

The only problem is that as you go lower in size it takes longer to draw a sample.
 
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