What is Used Oil Analysis
At the time of a motor oil or hydraulic oil change, a small sample of the used oil (50ml) is retained. The sample is sent to a laboratory for analysis.
Why Test the Used Oil
An analysis can spot wear and contaminants and monitor the oil condition in:
- gasoline engines
- propane engines
- natural gas powered engines
- automotive transmissions
- industrial gearboxes
- hydraulic/industrial circulating oil systems
This analysis in invaluable in preventing costly equipment breakdowns, and in setting up a "preventive maintenance" program.
How is the Test Performed
After the laboratory receives the sample, a series of tests are performed. The table below is a listing of each test, and the conditions detected by the test. All tests are not necessarily performed as each laboratory has an established series of tests.
| Tests |
Conditions Detected |
| # |
Abnormal
Wear |
Fuel
Dilution |
Dirt |
Water |
Coolant |
Incorrect
Oil |
Oxidation |
Additive
Depletion |
| Glycol Test |
|
|
|
|
* |
|
|
|
| Viscosity |
|
* |
|
|
|
* |
|
|
| Appearance/Odor |
|
* |
* |
* |
* |
|
* |
|
| Spectrometric Analysis |
* |
|
* |
|
* |
* |
|
|
| Alkaline Reserve |
|
|
|
|
|
* |
|
* |
| Blotter Spot Test |
|
|
* |
* |
|
|
* |
|
| Water Content |
|
|
|
* |
|
|
|
|
| Distillation |
|
* |
|
|
|
|
|
|
| Flash Point |
|
* |
|
|
|
|
|
|
Spectrometric Analysis
In the spectrometer, an oil is electrically excited to the point where light is emitted. Each element present in the burning oil emits a light of its own particular color and frequency. The spectrometers translates the intensity of this rainbow of colors into a computerized readout.
A typical report from this test would list nine(9) major wear metals for industrial gear oil and hydraulic oil. Twelve(12) are reported for automotive oils.
The computer compares the amount of wear metals present with a fresh oil sample, and also records of samples from similar equipment. Also, the computer compares the output from previous samples taken from the same piece of equipment to establish wear trends.
The report should summarize the results for the customer, and recommend remedial action.
Wear Metal Origins Table
| Wear Metal |
Origin |
| Aluminum |
Pistons, bearings, blower/turbo charges, pump vanes, thrust washers and bearings, blocks, oil pump bushings, housing clutches, impellers, rotors |
| Chromium |
Rings, roller-taper bearings, liners, exhaust valves, coolant, rods, spools, gears, shafts, anti-friction bearings |
| Copper |
Bearings, thrust washers, bushings, oil coolers, oil additives, wrist-pin bushings, cam bushings, valve-train bushings, governor, oil pump, stearing discs, pump thrust plates and pistons, injector shields, wet clutches |
| Iron |
Cylinders, crankshafts, valve train, piston rings, clutch, pistons, rings, gears, bearings, liners, shafts, plates, blocks, camshafts, pumps, PTO, shift spools, cylinder bores and rods, piping and components of circulating oil systems. |
| Lead |
Bearings, gasoline additives, oil additives |
| Magnesium |
Oil detergent, oil alkaline reserve |
| Molybdenum |
Oil additive, friction modifier |
| Nickel |
Alloy, gear plating, valve guides and ring bands, shafts, anti-friction bearings |
| Silver |
Wrist-pin bushings, anti-friction bearings, silver solder |
| Tin |
Bearings, piston plating, alloy of bronze(copper/tin), bushings |
Silica
(silicon-Silicone) |
Ingested dirt and sand, gasket sealant, oil anti-foam additive, anti-freeze additive |
| Zinc |
Anti-wear oil additive ( zinc dialkyl-dithio-phosphate), galvanized parts in circulating oil systems |
Operational Benefits of Testing
It is the backbone of any preventive maintenance program. A summary of the benefits are as follows:
- Reduces unnecessary major repairs by detecting lubrication problems early. This provides time to schedule maintenance, and order replacement parts.
- Eliminates premature oil change out by establishing correct drain intervals required by individual components under given operating and environmental conditions. The savings can be significant for a fleet operation.
- Reduces expensive, unscheduled down-time caused by the unexpected failure of components.
- Evaluates used-equipment purchases. A single oil sample prior to a purchase will give the purchaser a good idea of the internal condition of the engine, and transmission.
- Allows the initial tracking of warranty problems. Preliminary data can be presented to support a warranty claim.
- Determines the overall performance level of maintenance facilities and personnel.
Where Can I Have the Oil Tested
If you are a major fleet customer, contact your Lube Oil Sales Representative to arrange testing.
Major oil companies, service centers, and local labs in your area should be able to provide information on testing.
How Much Does a Test Cost
I cannot provide a $ amount because it could vary significantly from area to area. But, use your negotiating skills as a consumer of a particular brand to obtain a deal from your supplier.
Revalent Links
OilTech Online produced by Darrin Clarke has some excellent resource material on Oil Testing and Predictive Maintenance Topics.
Top Source Technologies, Inc.
markets the patented
MotorCheck™ On-Site Analyzer, an "oil analysis mini-lab in a
box". "The Analyzer is designed to work in a high-volume, quick turnaround
environment where the accuracy featured by central labs is not as important as being able to monitor
trends fast and consistently".
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