Bahasa
Hindi
Arabic
Spanish
For the everyday mechanic, evaluating grease quality doesn’t always rely on specification sheets. Instead, they often rely on what they can feel: the look, the texture, and the smell of the product. While these indicators can be a good starting point, they can also be misleading. This guide will break down these unscientific tests and explain what really matters when it comes to grease performance.
“Sight” Test—“The look”: First Impressions
A common notion is that the best quality greases are pale, transparent, like honey. This visual assessment is often tied to the quality of the base oil used in its formulation. High-quality, pure base oils are often clear and pale in color, resulting in a finished grease with a similarly clean appearance. Conversely, darker, less transparent greases may be made with lower quality or recycled base oils. While light color and transparency are a good sign, they are only the beginning of a true quality assessment.
“Touch” Test—“The texture”: Stiffness vs. High Temperature Performance
The feel of a grease is perhaps the most misleading metric. Many people believe that the thicker and stiffer a grease is at ambient temperatures (25oC-35oC), the higher its load-carrying capacity. This leads to confusion between two different measurements: viscosity (Flow) and stiffness (thickness). The stiffness of a grease is scientifically measured by the NLGI scale, with higher numbers indicating stiffer greases. While it is true that stiffer greases can handle higher loads, the feel of stiffness at ambient temperatures does not tell the whole story.
A lower quality grease, Calcium NGLI3 may feel thicker and stiffer at ambient temperature, but it has a low dropping point (e.g. 80°C), which is the limit at which the grease “melts” and changes from a solid to a liquid. If the operating temperature of the equipment is at 120°C and exceeds Calcium grease dropping point, the Calcium grease will fail. On the other hand, a high quality, Lithium NGL2 grease will feel “thinner” at ambient temperature but has a much higher dropping point (e.g. 180°C), allowing the grease to function perfectly under the same operating temperature conditions of 120°C. To give you an idea of the difference, the typical dropping point of a Calcium based grease is 80°C, whereas our MP/EP Lithium based grease is above 180°C, and our Lithium Complex grease is above 250°C. This is why the dropping point is a much more important factor than a simple sensory test.
The final “Smell” test – “The Odor”: Mild Vs Bad
While base oils are not completely odorless, good quality base oils will have a very mild odor. A strong, pungent, or burnt odor may indicate that recycled oil has been used in the manufacturing process. The absence of a strong odor from the oil is a positive sign, but like other indicators, it is not a sure measure of performance.
Scientific Standards
While your senses can provide initial clues, they are no substitute for technical specifications. The most reliable way to ensure you are using a high-quality grease is to check the product’s specification sheet, which provides objective specifications for properties such as NLGI grades, dropping points, and other key performance indicators. By relying on these scientific standards, you can make informed choices that ensure the longevity and performance of your equipment.
For the average mechanic, evaluating grease quality does not always begin with reading technical data sheets. Instead, they often rely on what they can perceive: the appearance, feel, and even smell of the product. While these sensory indicators can serve as a starting point, they may also be misleading. This guide breaks down these non-scientific “tests” and explains what really matters when it comes to grease performance.
The “Appearance” Test – First Visual Impressions
A common belief is that the best-quality grease is light-colored, transparent, and honey-like. This visual assessment is often linked to the quality of the base oil used in its formulation. High-purity, premium base oils tend to be clearer and lighter in color, resulting in a finished grease that looks clean and translucent. By contrast, darker, more opaque greases may be produced using lower-quality or recycled base oils. While a lighter, clearer appearance can be a positive sign, it is only the beginning of a true quality evaluation.
The final “Smell” test – “The Odor”: Mild Vs Bad
While base oils are not completely odorless, good quality base oils will have a very mild odor. A strong, pungent, or burnt odor may indicate that recycled oil has been used in the manufacturing process. The absence of a strong odor from the oil is a positive sign, but like other indicators, it is not a sure measure of performance.
Scientific Standards
While your senses can provide initial clues, they are no substitute for technical specifications. The most reliable way to ensure you are using a high-quality grease is to check the product’s specification sheet, which provides objective specifications for properties such as NLGI grades, dropping points, and other key performance indicators. By relying on these scientific standards and your experiences, you can make informed choices that ensure the longevity and performance of your equipment.
