Can engine oils of different brands be mixed?
2 Answers
Engine oils of different brands cannot be mixed. Engine oils from different brands and grades are formulated with various additives based on the working characteristics of different engines and the requirements of their operating environments, resulting in differences in viscosity, anti-wear properties, corrosion resistance, anti-knock performance, and volatility. Mixing them may degrade the oil's performance and even cause damage to the engine. Engine oil, also known as engine lubricant, serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption. It is often referred to as the 'blood' of a car. Engine oil consists of two main components: base oil and additives.
Speaking of mixing different brands of engine oil, I’ll give some advice from a professional auto repair perspective. It’s not recommended to mix them because each brand has its own proprietary formula, with significant differences in base oils and additives. Mixing can cause chemical reactions that may lead to sediment buildup, clogging oil passages or the oil pump. This affects lubrication efficiency, accelerates engine wear, and may even cause overheating issues. I’ve personally seen cases where engines became much noisier after mixing oils, leading to costly major repairs. It’s best to stick with the same brand and grade of oil and thoroughly flush out the old oil during changes. In emergencies where oil is low, adding a small amount of another brand can suffice for short trips, but be sure to visit a professional shop for a full replacement as soon as possible. Maintaining the oil system properly extends vehicle lifespan, ensuring peace of mind and safety.
