What is the Difference Between Lubricating Oil and Grease?

[LaIsaac]

Lubricating grease and lubricating oil mainly differ in composition, pressure resistance, and function. In terms of composition: Lubricating grease is paste-like, belonging to a relatively viscous semi-solid fat. It is made by adding thickeners to industrial oil. Lubricating oil is liquid, with strong fluidity and slightly higher volatility. In terms of pressure resistance: Lubricating grease has greater adsorption capacity on metal surfaces compared to lubricating oil and can form a more robust oil film, capable of withstanding higher working loads. This is due to the presence of a large amount of polar substances in the grease. Additionally, as a base grease, when polar additives are incorporated, it exhibits better receptivity than lubricating oil. In terms of function: Lubricating grease is often used on metal surfaces, serving to fill gaps and provide rust prevention. Lubricating oil is applied to various types of machinery, primarily functioning in lubrication, cooling, rust prevention, cleaning, sealing, and buffering.

[StClaire]

Engine oil is a liquid, commonly used in high-speed operating areas like inside engines. It flows smoothly to carry away heat and reduce friction. After years of driving, I've seen many car owners neglect oil changes, leading to engine overheating and failure, so regular oil changes are essential. Grease, on the other hand, is a semi-solid paste, sticky like butter, used in low-speed rotating parts such as wheel bearings or door hinges. It adheres persistently to prevent dust and seal, but doesn't require frequent replenishment. I think the key difference lies in their states and suitable scenarios—the strength of fluidity determines the choice, like oil being better for hydraulic systems while grease is more durable for fixed components. Understanding these can help you save unnecessary repair costs.

[McElliot]

From a daily car usage perspective, engine oil circulates like water in the engine and transmission to cool and lubricate friction surfaces. I usually change it every 5,000 kilometers to maintain smooth operation. Grease, on the other hand, sticks like a plaster to mechanical joints such as chassis ball joints or fan motor shafts. Once applied, it can last up to six months without drying out due to its excellent sealing, dust-proof properties, and poor fluidity. I once mistakenly used grease instead of oil when changing positions, which resulted in the machine seizing up—more harm than good. The difference lies in viscosity and durability. Fellow car enthusiasts, remember to use the right product in the right place for hassle-free and safe operation.

[LucyFitz]

Engine oil is a liquid base oil with additives, used in high-speed equipment like engines for flow cooling and reducing wear. Grease, on the other hand, is a semi-solid mixture similar to butter, applied to low-speed components such as bearings to provide long-lasting adhesion and prevent leakage. From mechanical principles, the difference lies in their physical state and the type of friction application, which affects maintenance strategies. Choosing the wrong one can lead to errors. Understanding this helps avoid machine problems.