Motor oil has to do more than look good on the bottle. It has to crank in the cold, hold the right viscosity at temperature, resist evaporation, control foam, fight oxidation, and protect metal from wear and corrosion. That is why lab testing matters. The core tests here show how oil earns its winter grade and operating viscosity, how its additive package appears under spectrographic analysis, and how contamination like water or particles is measured before it becomes a problem. Wear testing shows whether the chemistry can maintain a protective boundary layer under load. Foam and aeration testing show whether the oil keeps air out of the lubrication film, because air does not protect parts. Oxidation and corrosion testing show how quickly an oil forms varnish, thickens, or starts attacking metal surfaces. The point is simple: oil performance is measurable. Cold flow, volatility, wear scars, foam recovery, varnish buildup, and corrosion resistance all tell you whether a formulation will keep protecting when conditions get ugly.
Gale Banks continues his lubrication education inside Amsoil's chemistry lab, where engineer Dan Peterson and lab chemist Dale Beck explain how motor oils are validated before they ever go into an engine. After covering the ingredients and materials used in oil formulation in the prior segment, the focus here shifts to proof: a finished lubricant must be tested across a wide range of conditions to confirm that it performs as intended.
The lab tour follows the same logic used in oil development. Each test isolates a specific property such as cold-start viscosity, high-temperature viscosity, elemental composition, water contamination, particle cleanliness, volatility, wear protection, foaming tendency, oxidation resistance, corrosion protection, and low-temperature flow. Together, these tests establish whether an oil meets its grade, remains stable in service, protects hardware, and resists contamination and degradation.
The first stop is the cold crank simulator, a required test for motor oils and diesel oils that determines the winter rating in grades such as 5W and 10W. The instrument chills the sample and then measures the torque required to rotate a spindle in the oil. From that resistance to rotation at a specified temperature, the system calculates viscosity. The sample is pulled into the test cell, where the spindle turns inside the chilled oil.
The lab can program the chiller bath in 5-degree Celsius increments. A 5W-30, for example, is tested at -30 degrees Celsius, while a 10W oil is tested at -25 degrees Celsius. The system can pre-chill samples as low as -35 degrees Celsius. This is how the oil's low-temperature cranking behavior is quantified and how the winter portion of the viscosity grade is established.
Next are the viscosity baths used to determine the high-temperature grade. One bath runs at 100 degrees Celsius, roughly the temperature of boiling water, and this is where the 20, 30, and 40 weight classifications are determined for motor oils and diesel oils. Another bath runs at 40 degrees Celsius, which is used for products such as compressor fluids and ISO viscosity grades like ISO 46 and ISO 460.
These tests use glass viscometer tubes marked with upper and lower lines. Oil is drawn up to the upper mark and then allowed to flow downward under gravity. The time required for the sample to travel from the upper line to the lower line is measured and converted into viscosity using a calibration constant specific to each tube and temperature. Running both the 40 degrees Celsius and 100 degrees Celsius tests allows the lab to calculate viscosity index, and Amsoil applies these measurements to raw materials, blends, and finished products.
The lab also uses ICP, or inductively coupled plasma analysis, to identify the elemental makeup of an oil. In this process, the oil is burned in a plasma torch at temperatures above 3000 degrees Celsius. As the elements in the sample are excited, they emit light at characteristic wavelengths. A detector system with mirrors, reflectors, and sensors reads those wavelengths and identifies the elements present.
This spectrographic analysis can detect additives and wear metals including calcium, magnesium, iron, copper, aluminum, silica, boron, and molybdenum. The result is effectively a fingerprint for each product, allowing the lab to verify identity if there is ever a question about whether a sample is actually one of their oils.
The same instrument is also used for used-oil analysis. By monitoring increases in wear metals, the lab can track equipment condition and estimate wear rates in specific applications. In a diesel engine, for example, iron content can reveal how quickly ferrous components are wearing. The lab works closely with the mechanical test group, receiving samples from running test rigs and analyzing them over time. In some cases, the chemistry lab can identify a failure trend and tell the mechanical lab when a test should be stopped.
Another critical area is contamination control, beginning with water measurement. For many industrial lubricants, moisture content must remain extremely low, and incoming raw materials are checked as part of quality control. In northern climates, where rail cars and bulk deliveries are exposed to harsh winters, water contamination is a real concern. The lab first performs a simple crackle test to determine whether water is present at all. If moisture is detected, the entire rail car can be rejected.
When an exact value is needed, the sample goes into a dedicated water-content analyzer. The oil is injected into a heated bath, which evaporates the moisture and carries it through tubing into a reactor chamber. There, the instrument measures the conductivity of the solution. More moisture produces greater conductivity, allowing the system to quantify water content down to very low levels, such as 30 parts per million.
Banks notes that water is especially damaging in engine oil. The milky or mushy residue sometimes seen under an oil cap is an emulsified mixture of water and oil vapor. A small amount in that localized area is one thing, but if the entire sump looked like that, it would indicate serious contamination.
The lab also checks particulate cleanliness with a laser particle counter. This instrument shines light through the oil and detects the shadows cast by particles, counting both their number and size. This matters particularly for industrial lubricants and gear oils, where even a small amount of contamination can initiate pitting on heavily loaded gear teeth. Those pits can propagate into cracks and eventually lead to tooth failure. For that reason, the lab filters products to very low particle levels and verifies cleanliness before use.
To evaluate evaporation loss, the lab uses a Noack volatility tester. A small oil sample is heated to 250 degrees Celsius for one hour while a vacuum pulls off the lighter fractions. The purpose is to determine how much of the oil can volatilize under severe heat. If an oil is formulated with excessively light base stocks and too much viscosity modifier, it may evaporate out of the engine over time. This test helps ensure that the oil remains in service rather than boiling away. According to the discussion, Amsoil was the first to bring this test to the United States and help standardize it.
Wear protection is examined with a four-ball wear tester. In this setup, three steel balls sit in a cup filled with the oil sample, and a fourth ball is pressed against them from above in a rotating chuck. The machine allows the operator to set temperature, typically from 75 degrees Celsius up to 150 degrees Celsius, along with load in PSI and rotational speed. The test is run for an hour under ASTM-standardized conditions.
Afterward, the balls are examined under a microscope connected to a computer. The wear scars are photographed and measured, allowing direct comparison between products tested under identical conditions. Even at only 4x magnification, the difference can be obvious: one oil may leave a much smaller scar than another. This test focuses on boundary lubrication and the effectiveness of extreme-pressure, or EP, additives. Under these severe contact conditions, the chemistry must form sacrificial protective layers. If the additive system is inadequate, the wear scar grows rapidly and the bearing surface is visibly damaged.
Foaming tendency is tested in a foam bath used for industrial products, compressor fluids, and motor oils. Air is forced through the oil at a specified flow rate, much like a small bubbler, and the lab measures how much foam forms. The test is run at two temperatures, 24 degrees Celsius and 94 degrees Celsius, to represent both cooler and more engine-like conditions.
In the demonstration, a competitor's compressor oil is compared directly with one of Amsoil's compressor oils. The difference is dramatic: the competitor product develops a large foam head, while the Amsoil sample remains much calmer. The lab measures not only how much foam is generated but also how well the oil recovers after 10 minutes of settling.
This matters because entrained air is harmful to lubrication. Air in the oil reduces effective film strength, and compressed bubbles passing through tight, highly loaded clearances can contribute to damage. Banks points out that those bubbles also carry water, and when compressed under high pressure they can create superheated steam in localized contact zones. The test therefore evaluates both anti-foam behavior and the oil's ability to release air quickly.
The oxidation test uses a heated oil bath and a controlled oxygen supply to accelerate aging. In the setup shown, the lab runs nearly pure oxygen, about 95 percent, rather than normal atmospheric oxygen at roughly 20 percent. That increase in oxygen concentration greatly speeds the process, allowing the lab to compress months of field exposure into a much shorter period. According to the explanation, 13 days in this test can simulate about six months in a car.
The purpose is to study varnish formation, oxidation, and deposit buildup. Some samples remain relatively clean, with brown oil and little staining on the glass. Others quickly darken, leaving varnish in the reflux area and blackened oil with soot-like deposits. After the oxidation run, the aged oils are sent back through other tests in the lab to measure viscosity increase, foam performance, oxidation effects, and other changes caused by service.
Rust prevention is evaluated with steel coupons coated in oil and then suspended in a cabinet maintained at 100 percent humidity. The coupons rotate continuously for weeks until failure. In the examples shown, properly formulated oil protects the steel for over a month, while a competitor product allows visible corrosion. This is especially important for seasonal equipment such as motorcycles and side-by-sides that may sit all winter with moisture exposure inside the engine.
The lab also performs copper corrosion testing on polished copper strips. These are immersed in oil for periods ranging from 3 to 24 hours at various temperatures. Sulfur-containing or otherwise corrosive formulations can attack the copper, turning the strip from bright and shiny to brown and dull. The results are compared against ASTM reference standards such as 1a or 3a. This is particularly relevant for yellow metals and for aftermarket additives, since some additive packages may contain sulfur or other materials that attack bearing surfaces rather than helping them.
The final demonstration is the cold pour point comparison, which makes low-temperature flow differences immediately visible. Oils are stored in a freezer at -35 degrees Celsius and then poured side by side. One sample flows relatively freely, while another comes out much more slowly, almost like honey. The point is simple: if oil cannot reach the parts that need lubrication during a cold start, it cannot do its job.
The most striking example compares two 15W-40 diesel oils at -35 degrees Celsius: Chevron Delo 15W-40 and Amsoil 15W-40 diesel engine oil. The visual difference is substantial, with the Amsoil product flowing far more readily. Banks notes that this kind of cold-start behavior matters in real service, especially in severe environments. The discussion references military JLTV engine cold starts at -40 degrees, where poor low-temperature flow makes cranking much harder.
The segment closes by emphasizing that chemistry-lab validation is only part of the process. After formulation and laboratory testing, the oils move on to the mechanical lab, where they are run in actual equipment. That next stage is where the lab data is tied directly to real hardware performance.