Can different brands of engine oil be mixed together?

[VanMalia]

Different brands of engine oil should not be mixed together. The oil must be completely replaced instead. Mixing different grades or brands of engine oil may cause chemical reactions between components, affecting the oil's performance. When changing engine oil, it is essential to thoroughly clean the residual old oil from the oil tank using cleaning oil before adding new oil. The oil filter should also be replaced simultaneously. Engine oil, also known as motor lubricant, serves multiple functions including lubrication and wear reduction, cooling, sealing against leaks, rust and corrosion prevention, as well as shock absorption. Engine oil consists of two main components: base oil and additives. The base oil is the primary constituent of lubricants, determining their fundamental properties, while additives compensate for and enhance the shortcomings of the base oil, providing additional performance characteristics. Additives are crucial components of lubricants.