What is the difference between engine oil and lubricating oil?
2 Answers
Engine oil and lubricating oil differ in scope: engine oil is a type of lubricating oil, but not all lubricating oils are engine oil. Engine oil is often referred to as the lifeblood of an engine, as it performs functions such as lubrication, cleaning, sealing, heat dissipation, buffering, and rust prevention within the engine. Without engine oil, the engine would not function properly. When adding engine oil, it is essential to ensure that the oil level remains between the min and max marks on the dipstick. If the oil level falls below the min mark, the engine may experience insufficient lubrication. Lubricating oil serves to reduce friction and wear between moving parts, acts as a coolant by absorbing heat from the combustion chamber and piston top to cool the engine and prevent overheating, and functions as a sealant by filling the gaps between piston rings and cylinder liners to prevent combustion pressure leakage.
I always emphasize this distinction in car club discussions: engine oil is actually a specific category, referring to lubricants specially designed for use inside the engine to reduce friction between pistons and cylinders while withstanding high temperatures and pressure; whereas lubricant is a broader term that includes engine oil, transmission fluid, gear oil, or industrial machinery oils. If you choose wrong, such as using regular lubricant in an engine, it can cause overheating, accelerated wear, and in severe cases, component failure. Engine oil contains special additives like API-rated ones that better clean and protect the engine system. For daily car use, it's best to consult the owner's manual - selecting the right engine oil type can extend engine life by thousands of kilometers. Remember to change oil regularly - the engine is the heart of your car and shouldn't be neglected.
